failsvsflailWhat's the difference?

Quick tell: fails is a verb, flail is a noun, so they fill different roles in a sentence.

Which to use

“fails” is a verb and “flail” is a noun - they look or sound alike but fill different roles in a sentence.

#4,600
“fails” frequency rank
#49,921
“flail” frequency rank
54521
confusion score

Side-by-Side Comparison

Feature fails flail
Definition third-person singular simple present indicative of fail A tool used for threshing, consisting of a long handle (handstock) with a shorter stick (swipple or swingle) attached with a short piece of chain, thong or similar material.

Where the eye mixes fails and flail

Muted = shared; highlighted = the visual trap. They share 4 letters in sequence. fails (CVVCC) and flail (CCVVC) run the same length but a different consonant-vowel pattern - the shape difference is usually the fastest tell.

5 ch
fails
5 ch
flail

Look-alike desk: fails vs flail

These two trip readers on the page rather than in the ear: fails is /feɪlz/ while flail is /fleɪl/. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 4 positions, and the parts of speech differ too (verb vs noun), which is usually the fastest check. Our composite confusion score for this pair is 54521, derived from the frequency rank of both members and their visual similarity.

fails is recorded at frequency rank #4,600, classified as averb, pronounced /feɪlz/. flail is at rank #49,921, tagged as anoun, pronounced /fleɪl/.

Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.

With a confusion score of 54521, this pair ranks #140,441 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of fails vs flail

Shared letters: afil. Private to "fails": s. Private to "flail": -.

"fails" · 5 letters · shape CVVCC  ·  "flail" · 5 letters · shape CCVVC

Known mistypes of this pair

  • fails ← afils · faills · failss · faisl · falis · ffails · fials
  • flail ← falil · fflail · flaill · flali · flial · fllail · lfail

Frequently Asked Questions

Is swapping "fails" for "flail" ever safe?
No - they are not even the same part of speech. "fails" is a verb and "flail" a noun, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "fails" or "flail"?
"fails" is the more common of the two: it sits at frequency rank #4,600 in our English list, against #49,921 for "flail". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.

  • Full dictionary entry for "fails" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "flail" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #140,441 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "fails" and "flail" also get mixed up with nearby pairs, the highest-scored neighbour is "Flagg vs flail". Nearby pair
  • Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes

Confusion rank #140,441 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list