Which to use
“FSB” is a name and “fus” is a verb - they look or sound alike but fill different roles in a sentence.
- #45,626
- “FSB” frequency rank
- #19,029
- “fus” frequency rank
- 64655
- confusion score
Side-by-Side Comparison
| Feature | FSB | fus |
|---|---|---|
| Definition | Service de renseignement de la Russie chargé des affaires de sécurité intérieure, successeur du service de la sécurité intérieure du KGB. | Première personne du singulier du passé simple de être. |
Where the eye mixes FSB and fus
Muted = shared; highlighted = the visual trap. They share 2 letters in sequence. FSB (CCC) and fus (CVC) run the same length but a different consonant-vowel pattern - the shape difference is usually the fastest tell.
Visual trap between FSB and fus
These two trip readers on the page rather than in the ear: FSB is \ɛf.ɛs.be\ while fus is \fy\. 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 (name vs verb), which is usually the fastest check. Our composite confusion score for this pair is 64655, derived from the frequency rank of both members and their visual similarity.
FSB is recorded at frequency rank #45,626, classified as aname, pronounced \ɛf.ɛs.be\. fus is at rank #19,029, tagged as averb, pronounced \fy\.
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 64655, this pair ranks #75,995 of 440,172 scored French confusable pairs - among the most confusable pairs.
Orthographic DNA of FSB vs fus
Shared letters: fs. Private to "FSB": b. Private to "fus": u.
"FSB" · 3 letters · shape CCC · "fus" · 3 letters · shape CVC
Frequently Asked Questions
Can "FSB" and "fus" be used interchangeably?
Which is more common, "FSB" or "fus"?
Useful next steps
Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.
- Full dictionary entry for "FSB" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "fus" - compare definitions side by side with the headword page. Word entry
- This pair ranks #75,995 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
- "FSB" and "fus" also get mixed up with nearby pairs, the highest-scored neighbour is "Fee vs FSB". Nearby pair
Confusion rank #75,995 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.