马马虎虎 vs 一模一样: Which Chengyu Fits?

How to decide

1. Use 马马虎虎 when the sentence points to so-so, careless, or just passable depending on context. Its tone is neutral to mildly negative, and the safest first test is whether the context resembles negative judgment, self-evaluation, everyday review.
2. Choose 一模一样 when the sentence points to exactly the same. Its tone is neutral descriptive, and the strongest clue usually looks closer to visual comparison, school comparison, product change.
3. The near-match area is small: both appear in everyday-speech and learning situations. The difference is not the Chinese topic label but the job each phrase performs in a sentence.
4. For natural English, compare so-so for 马马虎虎 and exactly the same for 一模一样, then check whether the surrounding sentence needs praise, warning, correction, or neutral description.

Wrong choice checks

• 马马虎虎: Do not translate it as a phrase about actual horses or tigers.
• 一模一样: Do not use it for vague similarity. Use 很像 when the match is loose.
• Do not let the story image do all the work. Check what the speaker is judging before you pick either phrase.
• Do not swap the two phrases just because they share a theme. A nearby topic can still carry the wrong social judgment.

Where this comparison comes from

• Both phrases have full dictionary entries with examples, source notes, and usage boundaries.
• The comparison uses entry-level source references instead of adding new historical claims on the compare page.
• The page exists because learners often need to reject a near phrase, not only recognize a single chengyu.

• 马马虎虎: CC-CEDICT dictionary cross-check via MDBG
  Used to cross-check the modern headword, pinyin, and broad dictionary sense for 马马虎虎; this is not treated as the story source.
• 马马虎虎: Wiktionary open lexical reference
  Used as an open lexical reference for English readers checking the headword and common translation range for 马马虎虎; usage decisions still come from examples on this page.
• 马马虎虎: Chinese Text Project dictionary locator
  Used as a classical-text locator and Chinese reference cross-check for 马马虎虎; the entry still rewrites the learner explanation in this site's own order.
• 一模一样: CC-CEDICT dictionary cross-check via MDBG
  Used to cross-check the modern headword, pinyin, and broad dictionary sense for 一模一样; this is not treated as the story source.
• 一模一样: Wiktionary open lexical reference
  Used as an open lexical reference for English readers checking the headword and common translation range for 一模一样; usage decisions still come from examples on this page.
• 一模一样: Chinese Text Project dictionary locator
  Used as a classical-text locator and Chinese reference cross-check for 一模一样; the entry still rewrites the learner explanation in this site's own order.

Visual memory: The board keeps both phrases visible at once so the learner decides by tone, context, and mistake boundary.