firthvsfitWhat's the difference?

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

Which to use

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

#22,972
“firth” frequency rank
#1,185
“fit” frequency rank
24157
confusion score

Side-by-Side Comparison

Feature firth fit
Definition An arm or inlet of the sea; a river estuary. Suitable; proper

Where the eye mixes firth and fit

Muted = shared; highlighted = the visual trap. They share 3 letters in sequence.

5 ch
firth
3 ch
fit

Spelling & Dictionary Insight

These two trip readers on the page rather than in the ear: firth is /fɜːθ/ while fit is /fɪt/. 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 (noun vs adjective), which is usually the fastest check. Our composite confusion score for this pair is 24157, derived from the frequency rank of both members and their visual similarity.

firth is recorded at frequency rank #22,972, classified as anoun, pronounced /fɜːθ/. fit is at rank #1,185, tagged as anadj, pronounced /fɪt/.

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 24157, this pair ranks #404,040 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of firth vs fit

Shared letters: fit. Private to "firth": hr. Private to "fit": -.

"firth" · 5 letters · shape CVCCC  ·  "fit" · 3 letters · shape CVC

Known mistypes of this pair

  • firthffirth · firht · firrth · firthh · firtth · fitrh · ifrth

Frequently Asked Questions

Can "firth" and "fit" be used interchangeably?
No - they are not even the same part of speech. "firth" is a noun and "fit" an adjective, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "firth" or "fit"?
"fit" is the more common of the two: it sits at frequency rank #1,185 in our English list, against #22,972 for "firth". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

What to do next

You've compared "firth" and "fit". Here's where to go from here.

  • Full dictionary entry for "firth" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "fit" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #404,040 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "firth" and "fit" also get mixed up with nearby pairs, the highest-scored neighbour is "firth vs frith". 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

PlainSpell is a reference corpus, not spelling advice. Verify unusual forms in context.

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

Source: FrequencyWords open word-frequency list