Which to use
“fallu” is a verb and “fill” is an adverb - they look or sound alike but fill different roles in a sentence.
- #3,331
- “fallu” frequency rank
- #38,807
- “fill” frequency rank
- 42138
- confusion score
Side-by-Side Comparison
| Feature | fallu | fill |
|---|---|---|
| Definition | Participe passé de falloir. | Aussitôt, immédiatement, sitôt, tout de suite, d’abord. |
Where the eye mixes fallu and fill
Muted = shared; highlighted = the visual trap. They share 3 letters in sequence.
Why the eye confuses fallu with fill
These two trip readers on the page rather than in the ear: fallu is \fa.ly\ while fill is \ˈfiɫ\. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (verb vs adverb), which is usually the fastest check. Our composite confusion score for this pair is 42138, derived from the frequency rank of both members and their visual similarity.
fallu is recorded at frequency rank #3,331, classified as averb, pronounced \fa.ly\. fill is at rank #38,807, tagged as anadv, pronounced \ˈfiɫ\.
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 42138, this pair ranks #227,929 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of fallu vs fill
Shared letters: fl. Private to "fallu": au. Private to "fill": i.
"fallu" · 5 letters · shape CVCCV · "fill" · 4 letters · shape CVCC
Known mistypes of this pair
Frequently Asked Questions
Is swapping "fallu" for "fill" ever safe?
Which is more common, "fallu" or "fill"?
Useful next steps
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "fallu" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "fill" - compare definitions side by side with the headword page. Word entry
- This pair ranks #227,929 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
- "fallu" and "fill" also get mixed up with nearby pairs, the highest-scored neighbour is "filez vs fill". 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 #227,929 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.