foulvsfunWhat's the difference?

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

Which to use

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

#6,574
“foul” frequency rank
#502
“fun” frequency rank
7076
confusion score

Side-by-Side Comparison

Feature foul fun
Definition Covered with, or containing unclean matter; dirty. Amusement, enjoyment or pleasure.

Where the eye mixes foul and fun

Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.

4 ch
foul
3 ch
fun

Why the eye confuses foul with fun

These two trip readers on the page rather than in the ear: foul is /faʊl/ while fun is /fʌn/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (adjective vs noun), which is usually the fastest check. Our composite confusion score for this pair is 7076, derived from the frequency rank of both members and their visual similarity.

foul is recorded at frequency rank #6,574, classified as anadj, pronounced /faʊl/. fun is at rank #502, tagged as anoun, pronounced /fʌn/.

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 7076, this pair ranks #508,680 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of foul vs fun

Shared letters: fu. Private to "foul": lo. Private to "fun": n.

"foul" · 4 letters · shape CVVC  ·  "fun" · 3 letters · shape CVC

Known mistypes of this pair

  • foulffoul · folu · foull · fuol · oful

Frequently Asked Questions

Do "foul" and "fun" mean the same thing in a sentence?
No - they are not even the same part of speech. "foul" is an adjective and "fun" a noun, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "foul" or "fun"?
"fun" is the more common of the two: it sits at frequency rank #502 in our English list, against #6,574 for "foul". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

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 "foul" 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 #508,680 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "foul" and "fun" also get mixed up with nearby pairs, the highest-scored neighbour is "FOMO vs foul". 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

Confusion rank #508,680 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list