Which to use
“FSB” is a name and “fun” is an adjective - they look or sound alike but fill different roles in a sentence.
- #45,626
- “FSB” frequency rank
- #5,870
- “fun” frequency rank
- 51496
- confusion score
Side-by-Side Comparison
| Feature | FSB | fun |
|---|---|---|
| Definition | Service de renseignement de la Russie chargé des affaires de sécurité intérieure, successeur du service de la sécurité intérieure du KGB. | Amusant. |
Where the eye mixes FSB and fun
Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.
Why the eye confuses FSB with fun
These two trip readers on the page rather than in the ear: FSB is \ɛf.ɛs.be\ while fun is \fœn\. 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 adjective), which is usually the fastest check. Our composite confusion score for this pair is 51496, 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\. fun is at rank #5,870, tagged as anadj, pronounced \fœn\.
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 51496, this pair ranks #154,556 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of FSB vs fun
Shared letters: f. Private to "FSB": bs. Private to "fun": nu.
"FSB" · 3 letters · shape CCC · "fun" · 3 letters · shape CVC
Frequently Asked Questions
Do "FSB" and "fun" mean the same thing in a sentence?
Which is more common, "FSB" or "fun"?
What to do next
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "FSB" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "fun" - compare definitions side by side with the headword page. Word entry
- This pair ranks #154,556 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
- "FSB" and "fun" also get mixed up with nearby pairs, the highest-scored neighbour is "Fee vs FSB". Nearby pair
Confusion rank #154,556 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.