fouvsfoxWhat's the difference?

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

Which to use

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

#1,063
“fou” frequency rank
#7,832
“fox” frequency rank
8895
confusion score

Side-by-Side Comparison

Feature fou fox
Definition Qualifie une personne qui a perdu la raison, qui est atteinte d’aliénation mentale. Race de chien, abréviation de fox-terrier.

Where the eye mixes fou and fox

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

3 ch
fou
3 ch
fox

Why the eye confuses fou with fox

These two trip readers on the page rather than in the ear: fou is \fu\ while fox is \fɔks\. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - u in “fou” becomes x in “fox”, and the parts of speech differ too (adjective vs noun), which is usually the fastest check. Our composite confusion score for this pair is 8895, derived from the frequency rank of both members and their visual similarity.

fou is recorded at frequency rank #1,063, classified as anadj, pronounced \fu\. fox is at rank #7,832, tagged as anoun, pronounced \fɔks\.

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 8895, this pair ranks #418,508 of 440,172 scored French confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of fou vs fox

Shared letters: fo. Private to "fou": u. Private to "fox": x.

"fou" · 3 letters · shape CVV  ·  "fox" · 3 letters · shape CVC

Frequently Asked Questions

Can "fou" and "fox" be used interchangeably?
No - they are not even the same part of speech. "fou" is an adjective and "fox" a noun, so a sentence built for one is usually ungrammatical with the other.
In ordinary French text, does "fou" or "fox" show up more?
"fou" is the more common of the two: it sits at frequency rank #1,063 in our French list, against #7,832 for "fox". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

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 "fou" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "fox" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #418,508 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "fou" and "fox" also get mixed up with nearby pairs, the highest-scored neighbour is "Fee vs fox". Nearby pair

Confusion rank #418,508 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list