Which to use
“fai” is a verb and “FSB” is a name - they look or sound alike but fill different roles in a sentence.
- #11,967
- “fai” frequency rank
- #45,626
- “FSB” frequency rank
- 57593
- confusion score
Side-by-Side Comparison
| Feature | fai | FSB |
|---|---|---|
| Definition | Deuxième personne du pluriel de l’indicatif présent de fer. | Service de renseignement de la Russie chargé des affaires de sécurité intérieure, successeur du service de la sécurité intérieure du KGB. |
Where the eye mixes fai and FSB
Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.
Visual trap between fai and FSB
These two trip readers on the page rather than in the ear: fai is [ˈfa.i] while FSB is \ɛf.ɛs.be\. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 2 positions, and the parts of speech differ too (verb vs name), which is usually the fastest check. Our composite confusion score for this pair is 57593, derived from the frequency rank of both members and their visual similarity.
fai is recorded at frequency rank #11,967, classified as averb, pronounced [ˈfa.i]. FSB is at rank #45,626, tagged as aname, pronounced \ɛf.ɛs.be\.
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 57593, this pair ranks #114,096 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of fai vs FSB
Shared letters: f. Private to "fai": ai. Private to "FSB": bs.
"fai" · 3 letters · shape CVV · "FSB" · 3 letters · shape CCC
Frequently Asked Questions
Is swapping "fai" for "FSB" ever safe?
Frequency check: "fai" vs "FSB" - which ranks higher?
Useful next steps
Eye-level mix-up between "fai" and "FSB" is sorted above. Next: full entries or other pairs that share a letter shape.
- Full dictionary entry for "fai" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "FSB" - compare definitions side by side with the headword page. Word entry
- This pair ranks #114,096 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
- "fai" and "FSB" also get mixed up with nearby pairs, the highest-scored neighbour is "Fee vs FSB". Nearby pair
Confusion rank #114,096 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.