fitvsFSBWhich spelling fits?

Quick tell: fit is a adjective, FSB is a noun, so they fill different roles in a sentence.

Which to use

“fit” is an adjective and “FSB” is a noun - they look or sound alike but fill different roles in a sentence.

#3,655
“fit” frequency rank
#41,175
“FSB” frequency rank
44830
confusion score

Side-by-Side Comparison

Feature fit FSB
Definition in guter gesundheitlicher, sportlicher, physischer, psychischer Verfassung; gut vorbereitet russischer Inlandsgeheimdienst und Geheimpolizei

Where the eye mixes fit and FSB

Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.

3 ch
fit
3 ch
FSB

Look-alike desk: fit vs FSB

These two trip readers on the page rather than in the ear: fit is [fɪt] while FSB is [ɛfʔɛsˈbeː]. 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 (adjective vs noun), which is usually the fastest check. Our composite confusion score for this pair is 44830, derived from the frequency rank of both members and their visual similarity.

fit is recorded at frequency rank #3,655, classified as anadj, pronounced [fɪt]. FSB is at rank #41,175, tagged as anoun, pronounced [ɛfʔɛsˈbeː].

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 44830, this pair ranks #1,373,378 of 2,006,359 scored German confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of fit vs FSB

Shared letters: f. Private to "fit": it. Private to "FSB": bs.

"fit" · 3 letters · shape CVC  ·  "FSB" · 3 letters · shape CCC

Frequently Asked Questions

Can "fit" and "FSB" be used interchangeably?
No - they are not even the same part of speech. "fit" is an adjective and "FSB" a noun, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "fit" or "FSB"?
"fit" is the more common of the two: it sits at frequency rank #3,655 in our German list, against #41,175 for "FSB". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

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 "fit" 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 #1,373,378 of 2,006,359 scored German confusable pairs in this corpus vintage. Corpus statistics
  • "fit" and "FSB" also get mixed up with nearby pairs, the highest-scored neighbour is "fist vs FSB". Nearby pair

Confusion rank #1,373,378 of 2,006,359 scored German pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list