CYChengyu Dictionary

Chengyu meaning

口是心非 (kǒu shì xīn fēi)

to say yes while thinking otherwise

Plain Answer

Source: Common speech-heart contrast in Chinese usage. Treated here as proverb image; read it first as a sentence-level judgment.

Core meaning: 口是心非 means to say yes while thinking otherwise: Used when a person's spoken words do not match their real thoughts, feelings, or intention.

Practice this meaning
Label
negative / common written and spoken
Best objects
social reaction, apology sincerity, contrast boundary
Do not use when
Do not use 口是心非 for a scene that only shares one surface word with the meaning. If the problem is closer to 口蜜腹剑 or the contrast points toward 光明磊落, choose that nearby entry instead of stretching this one.

Use: Use 口是心非 when the social reaction sentence shows the object, cause, and tone clearly. Avoid: Avoid 口是心非 when the sentence only sounds related, lacks evidence, or needs a plainer word.

social reaction他嘴上说没关系，表情却很冷，大家都觉得他有点口是心非。Ta zuishang shuo mei guanxi, biaoqing que hen leng, dajia dou juede ta youdian kou shi xin fei.He said it was fine, but his expression was cold, so everyone felt he was saying one thing and meaning another.

Next: Read the examples, then compare 口蜜腹剑 before practicing 口是心非 in the focused quiz.

Often studied with: 口蜜腹剑, 以心换心, 察言观色

Read This First

口是心非 is introduced here through a proverb or image-based phrase with a learner-safe source boundary; the source label is Common speech-heart contrast in Chinese usage, and the page separates that background from modern sentence choice.

口是心非 means to say yes while thinking otherwise. The important first reading is Used when a person's spoken words do not match their real thoughts, feelings, or intention. This is a negative phrase in normal use, so the sentence must show the judgment clearly.

Use 口是心非 when the object, cause, and tone match examples such as social reaction, apology sincerity, contrast boundary; then compare 口蜜腹剑 and 以心换心 before writing your own sentence.

Avoid 口是心非 when the sentence only shares a broad topic, when the tone would be unfair to the person being described, or when a plainer word would be clearer than a chengyu.

Start with this cue: social reaction plus a visible reason.

Meaning and Translation Notes

Used when a person's spoken words do not match their real thoughts, feelings, or intention.

Literal meaning

the mouth says yes, the heart says no

  • 口是 / the mouth says yes
  • 心非 / the heart says no

English equivalents

  • say one thing and mean another near

    Use this when spoken words do not match the person's real thought, feeling, or intention.

  • speak against one's real feelings plain

    say one thing and mean another is natural, while words and heart do not match explains the literal logic

  • words and heart do not match plain

    This is safer when the audience needs the meaning without extra cultural explanation.

How To Use It

Use 口是心非 when the reader can see why to say yes while thinking otherwise is the exact judgment, not just the topic. A strong sentence names the actor, the thing being judged, and the evidence that makes this idiom more precise than an ordinary adjective.

  • Use it when spoken words do not match the person's real thought, feeling, or intention.
  • The tone is critical or observant, so the surrounding sentence should make the judgment visible.
  • It works in social reaction, apology sincerity, contrast boundary contexts when the boundary is clear.

Common Mistakes

Do not use 口是心非 for a scene that only shares one surface word with the meaning. If the problem is closer to 口蜜腹剑 or the contrast points toward 光明磊落, choose that nearby entry instead of stretching this one.

  • Do not use it when the person changes their mind honestly or uses polite wording without hiding a different intention.
  • Do not choose it only because the English gloss "say one thing and mean another" feels close; compare kou-mi-fu-jian first.

Wrong Use Clinic

The most useful check is often the phrase you should reject.

  1. The learner wants to sound more idiomatic but has only a broad topic match for 口是心非.

    The sentence drops in 口是心非 without showing the cause, object, or tone that would make the idiom necessary.

    Fix: Rewrite the sentence so the evidence for to say yes while thinking otherwise appears before or after the phrase.

    口是心非 fails in this case because a chengyu is not decoration; it must name the exact judgment the sentence is making.

    Compare kou mi fu jian

  2. The learner wants to say the opposite or a neighboring idea and chooses 口是心非 because it feels familiar.

    The sentence uses 口是心非, but the described situation points to a different cause, time point, or social attitude.

    Fix: Compare the sentence with 光明磊落 and choose the phrase whose boundary explains the situation with less force.

    口是心非 becomes misleading when the nearby phrase would identify the real problem more cleanly.

    Compare guang ming lei luo

  3. The learner has the right meaning area for 口是心非 but ignores register and emotional force.

    The sentence uses 口是心非 directly about a person, yet gives no softening context or evidence for such a critical or observant judgment.

    Fix: Add the observed behavior first, or choose 以心换心 if the sentence needs a gentler learning path.

    口是心非 can sound heavier than a short English gloss. The reader needs enough context to see why the tone is fair.

    Compare yi xin huan xin

  4. The learner remembers the origin image of 口是心非 but applies it to the wrong object.

    The sentence names an image or story detail, but the real object being judged would be better explained by another chengyu.

    Fix: Name the object first. If the object points toward 开门见山, use that contrast instead.

    口是心非 should follow the judgment, not the most memorable image. Story memory is useful only when it supports the sentence-level decision.

    Compare kai men jian shan

Chengyu Often Studied Together

Use these clusters to build sentence-level judgment instead of memorizing a single gloss.

  1. 口是心非 with nearby learner choices

    口是心非 is often studied beside 口蜜腹剑 and 以心换心 because the words share a theme while asking the learner to judge a different cause, tone, or timing.

    老师先让学生解释口是心非，再比较口蜜腹剑和以心换心，这样不会只凭英文近义词选答案。

    kou mi fu jianyi xin huan xin

  2. 口是心非 with contrast checks

    口是心非 becomes easier to use when it is contrasted with 察言观色 and 光明磊落; the contrast forces the writer to decide whether the sentence is praise, warning, correction, or neutral description.

    写作练习里先用口是心非造句，再换成察言观色，观察判断方向怎样改变。

    cha yan guan seguang ming lei luokou mi fu jian

  3. 口是心非 in example-building drills

    口是心非 should be practiced with 口蜜腹剑 and 察言观色 because examples reveal whether the learner is choosing by meaning, tone, or only by a remembered image.

    课堂上先用口是心非写一个有证据的句子，再换成口蜜腹剑或察言观色说明判断为什么改变。

    kou mi fu jiancha yan guan seyi xin huan xin

  4. 口是心非 in story and source review

    口是心非 links best with 以心换心 and 光明磊落 when the learner is checking whether a source image truly supports a modern sentence.

    复习出处时，不要只背口是心非的故事，还要比较以心换心，看哪个成语更能解释现代句子。

    yi xin huan xinguang ming lei luokou mi fu jian

Learner Guide

Use these notes when deciding whether this chengyu fits a real sentence.

Use 口是心非 when spoken words do not match the person's real thought, feeling, or intention. This first test keeps the phrase from spreading across every nearby topic. Before using it, identify the speaker, the object being judged, and the reason a plain word would miss the Chinese nuance.

For English translation, say one thing and mean another is natural, while words and heart do not match explains the literal logic. Do not choose an English phrase only because it sounds idiomatic. The translation should preserve tone, register, and the situation logic before it tries to sound compact.

The main misuse risk is when the person changes their mind honestly or uses polite wording without hiding a different intention. That boundary matters because chengyu often share a theme while judging different causes, time points, or social attitudes. A nearby phrase can be familiar and still be wrong.

Before using it in your own sentence, show the spoken words, the inner mismatch, and the clue that reveals the difference. Then compare the sentence with kou-mi-fu-jian and yi-xin-huan-xin. If one nearby entry explains the situation with less force or more precision, choose that entry instead.

Before using 口是心非, write the plain English idea first. If the plain sentence already says everything naturally, the chengyu must add a sharper judgment, cultural image, or tone. If it does not add one of those, leave the plain wording alone.

A good 口是心非 sentence contains an object and evidence. The object is the person, plan, habit, result, or scene being judged. The evidence is the reason the phrase fits. Without both parts, the idiom may look learned but feel empty.

Compare 口是心非 with 口蜜腹剑 and 光明磊落 before finalizing a sentence. The goal is not to memorize synonyms; the goal is to reject the wrong phrase for a clear reason. That rejection is what turns recognition into usable knowledge.

When teaching or self-reviewing 口是心非, ask the learner to mark source, meaning, use case, wrong case, and one example. If any mark is missing, return to the entry section that supplies it rather than guessing from the headword alone.

social reaction is the first test zone for 口是心非, but it is not the only possible use. Before using the phrase, name the speaker, the object being judged, and the nearest tested context: social reaction, apology sincerity, contrast boundary, usage boundary, misuse boundary, comparison check, context setup, teacher correction. Then choose among say one thing and mean another, speak against one's real feelings, words and heart do not match as translation candidates and reject at least one candidate out loud. A useful final check is to compare the sentence with kou-mi-fu-jian and yi-xin-huan-xin; if one of those nearby entries explains the situation with less strain, the nearby phrase is the better learner choice.

When 口是心非 is translated as say one thing and mean another, the English should still preserve the phrase's tone. Keep critical or observant and the everyday-speech use area visible when the audience is still learning the idiom. If a short translation hides the warning "Do not use it when the person changes their mind honestly or uses polite wording without hiding a different intention.", choose a fuller English explanation instead. This matters because the strongest chengyu pages should help readers decide when not to use the most convenient English equivalent.

Example Sentences

Each example labels the situation so you can choose a natural English translation.

social reaction

他嘴上说没关系，表情却很冷，大家都觉得他有点口是心非。

Ta zuishang shuo mei guanxi, biaoqing que hen leng, dajia dou juede ta youdian kou shi xin fei.

He said it was fine, but his expression was cold, so everyone felt he was saying one thing and meaning another.

apology sincerity

道歉如果口是心非，听的人很快就能感觉出来。

Daoqian ruguo kou shi xin fei, ting de ren hen kuai jiu neng ganjue chulai.

If an apology is not sincere, listeners can quickly feel the mismatch between words and heart.

contrast boundary

口是心非不一定像口蜜腹剑那么恶意，有时只是心里不愿意。

Kou shi xin fei bu yiding xiang kou mi fu jian name eyi, youshi zhishi xinli buyuanyi.

口是心非 is not always as malicious as 口蜜腹剑; sometimes it only means inner reluctance.

usage boundary

只有原因和语气都清楚时，这句话才适合用口是心非。

zhi you yuan yin he yu qi dou qing chu shi zhe ju hua cai shi he yong kou shi xin fei

Only use 口是心非 when the cause and tone are both clear, not just because the topic feels nearby.

misuse boundary

如果只是普通情况，不要为了显得有文化而硬说口是心非。

ru guo zhi shi pu tong qing kuang bu yao wei le xian de you wen hua er ying shuo kou shi xin fei

If the situation is ordinary, do not force 口是心非 just to make the sentence sound more cultured.

comparison check

比较近义成语以后，再决定这里是不是应该写口是心非。

bi jiao jin yi cheng yu yi hou zai jue ding zhe li shi bu shi ying gai xie kou shi xin fei

After comparing nearby chengyu, decide whether 口是心非 is really the phrase the sentence needs.

context setup

这段话先说明对象和原因，所以口是心非读起来不突兀。

zhe duan hua xian shuo ming dui xiang he yuan yin suo yi kou shi xin fei du qi lai bu tu wu

The passage names the object and cause first, so 口是心非 does not feel abrupt.

teacher correction

老师让学生先解释为什么不用别的词，再用口是心非造句。

lao shi rang xue sheng xian jie shi wei shen me bu yong bie de ci zai yong kou shi xin fei zao ju

The teacher asks students to explain why another phrase would be wrong before writing a sentence with 口是心非.

Story and Cultural Context

口是心非 turns sincerity into a visible split: the mouth gives one answer while the heart holds another. The phrase is useful because it can be milder than deliberate betrayal. Modern learners usually need the phrase as a decision tool. It tells them when a situation has crossed a specific boundary, not merely which English word looks similar. In the examples here, the phrase is tested against social reaction, apology sincerity, contrast boundary so the reader can see how the meaning changes with use. The safest reading is to keep the image, the tone, and the social situation together. 口是心非 turns sincerity into a visible split: the mouth gives one answer while the heart holds another. The phrase is useful because it can be milder than deliberate betrayal. For English speakers, the useful memory is not only the literal image but the decision it makes possible. The examples test social reaction, apology sincerity, contrast boundary so the phrase remains tied to real use instead of becoming a decorative translation label. For this entry, the origin note is only the beginning of the explanation. The useful question is why 口是心非 survived as a portable judgment rather than as a decorative allusion. The image-based usage route gives the reader an image, but the modern sentence must still prove its own fit. A learner should ask three things: what concrete object is being judged, what evidence in the sentence supports that judgment, and what tone the phrase adds that a plain English adjective would not add. This is why the page tests 口是心非 through social reaction, apology sincerity, contrast boundary, usage boundary, misuse boundary; each context changes the pressure on the phrase and shows whether the idiom is acting as praise, warning, neutral description, or criticism. The story or usage background also has a translation boundary. 口是心非 can point toward say one thing and mean another, speak against one's real feelings, words and heart do not match, but those English choices are not interchangeable. One version may preserve the image, another may sound natural in a classroom answer, and another may be safer in a workplace or essay sentence. The entry therefore treats public references as source cards, not as a paragraph order to imitate. Headword checks, story labels, and English equivalents are separated first; only after that are they rebuilt into the learner path used here: answer, label, examples, wrong-use clinic, comparison, story, and practice. The most common failure is overextension. Because 口是心非 has a memorable surface, learners may reach for it whenever a topic feels close. The better habit is to compare it with 口蜜腹剑 and 以心换心 and with 光明磊落 and 开门见山 before writing. If the rejected phrase is hard to reject, the sentence probably has not supplied enough evidence. If the rejected phrase is easy to reject, the learner can explain the boundary and use 口是心非 with confidence. That is the practical purpose of the origin section: it turns cultural memory into a sentence-level decision instead of leaving the reader with a story and no next action.

Learning point: Words are only trustworthy when they match intention.

Editorial Notes

These notes turn the entry into a decision path, not a loose definition.

First answer before details

口是心非 should first be read as a decision about to say yes while thinking otherwise, not as a collectible story label. The image logic helps memory, but the reader's real task is to decide whether the modern sentence is making a negative judgment with enough evidence. Start with the object being described, then ask what happened, who is being judged, and whether the tone is fair. If those details are missing, the idiom will feel like learned decoration rather than useful Chinese. This first-answer rule also helps teachers and translators: they can explain the phrase quickly before deciding whether a longer story, comparison, or correction block is needed.

Example clinic

The examples for 口是心非 deliberately cover social reaction, apology sincerity, contrast boundary, usage boundary, misuse boundary because a learner needs more than one successful sentence before the phrase becomes usable. Read the Chinese sentence, then explain in plain English why this phrase is more precise than a simple adjective or loose translation. A strong example names the context, shows the evidence, and makes the tone visible. A weak example merely places the chengyu near a related topic. This habit prevents a common error: remembering the literal image but forgetting the social judgment carried by the phrase. When the example feels forced, return to the meaning line and choose a plainer wording.

Comparison boundary

Before using 口是心非, compare it with 口蜜腹剑 and 以心换心 and, when possible, with 光明磊落 and 开门见山. The comparison is not a synonym game. Nearby chengyu often share effort, caution, wisdom, or evaluation as a topic, while differing in cause, timing, and emotional force. A good learner sentence can explain why the rejected phrase fails. If that explanation is impossible, the chosen idiom is probably too loose. This is also the cleanest internal-link reason: the next page exists because it helps the reader reject a tempting but wrong choice. The comparison should leave a reusable rule, not merely another link to click.

Wrong-use trigger

口是心非 should be rejected when the sentence lacks an object, hides the reason for the judgment, or uses the idiom only because it sounds literary. The safest correction is to rewrite the sentence in plain English first, then add the chengyu only if it sharpens the meaning. If the tone becomes unfair, choose a gentler nearby phrase. If the source image is memorable but the modern object does not match, use the story only as background and do not force the idiom into the sentence. This wrong-use trigger is what keeps the entry from becoming a long but vague dictionary page.

Source synthesis note

口是心非 uses public references as checkpoints rather than as a structure to copy. One source may help with the headword, another with a story or image, and another with English translation range. The page then rebuilds those checks into its own learner order: short answer, label, examples, misuse, collocation, guide, story, and practice. This matters because a single-source paraphrase would give readers a familiar-looking article but not a better learning tool. The editorial value here is the decision path: what to use, what not to use, what to compare, and how to test the phrase in a new sentence.

Practice This Decision

Answer a focused quiz question, then come back to the examples and misuse clinic if the near phrase feels tempting.

Start focused quizReview mistakes first