Which to use
“fast” is an adverb and “Fs” is a noun - they look or sound alike but fill different roles in a sentence.
- #8,544
- “fast” frequency rank
- #28,962
- “Fs” frequency rank
- 37506
- confusion score
Side-by-Side Comparison
| Feature | fast | Fs |
|---|---|---|
| Definition | Presque, quasiment. | Pluriel de F. |
Where the eye mixes fast and Fs
Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.
Visual trap between fast and Fs
These two trip readers on the page rather than in the ear: fast is \fast\ while Fs is \ɛfs\. Spoken aloud the problem disappears. In writing it persists, because they differ by 2 letter(s) in length, and the parts of speech differ too (adverb vs noun), which is usually the fastest check. Our composite confusion score for this pair is 37506, derived from the frequency rank of both members and their visual similarity.
fast is recorded at frequency rank #8,544, classified as anadv, pronounced \fast\. Fs is at rank #28,962, tagged as anoun, pronounced \ɛfs\.
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 37506, this pair ranks #262,033 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of fast vs Fs
Shared letters: fs. Private to "fast": at. Private to "Fs": -.
"fast" · 4 letters · shape CVCC · "Fs" · 2 letters · shape CC
Known mistypes of this pair
- fast ← afst · fasst · fastt · fats · ffast · fsat
Frequently Asked Questions
Is swapping "fast" for "Fs" ever safe?
In ordinary French text, does "fast" or "Fs" show up more?
What to do next
Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.
- Full dictionary entry for "fast" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "Fs" - compare definitions side by side with the headword page. Word entry
- This pair ranks #262,033 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
- "fast" and "Fs" also get mixed up with nearby pairs, the highest-scored neighbour is "Fee vs Fs". 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 #262,033 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.