failsvsfasWhich spelling fits?

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

Which to use

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

#4,600
“fails” frequency rank
#27,454
“fas” frequency rank
32054
confusion score

Side-by-Side Comparison

Feature fails fas
Definition third-person singular simple present indicative of fail A border or fringe.

Letter map: fails vs fas

Shared letters muted; letters that set fails and fas apart highlighted. Shared run: 3. fails runs 5 letters (CVVCC) against fas's 3 (CVC) - the length gap alone is often enough to separate them once you know to check it.

5 ch
fails
3 ch
fas

Part-of-speech tell for fails / fas

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: fails is averb and fasanoun. On the page they differ by 2 letter(s) in length. Our composite confusion score for this pair is 32054, 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/. fas is at rank #27,454, tagged as anoun.

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 32054, this pair ranks #341,011 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of fails vs fas

Shared letters: afs. Private to "fails": il. Private to "fas": -.

"fails" · 5 letters · shape CVVCC  ·  "fas" · 3 letters · shape CVC

Known mistypes of this pair

  • fails ← afils · faills · failss · faisl · falis · ffails · fials

Frequently Asked Questions

Is swapping "fails" for "fas" ever safe?
No - they are not even the same part of speech. "fails" is a verb and "fas" a noun, so a sentence built for one is usually ungrammatical with the other.
In ordinary English text, does "fails" or "fas" show up more?
"fails" is the more common of the two: it sits at frequency rank #4,600 in our English list, against #27,454 for "fas". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Pair "fails" vs "fas" is on the table, pick a follow-up below.

  • Full dictionary entry for "fails" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "fas" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #341,011 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "fails" and "fas" also get mixed up with nearby pairs, the highest-scored neighbour is "fas vs foh". 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 #341,011 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