foivsfunWhich spelling fits?

Quick tell: foi is a verb, fun is an adjective, so they fill different roles in a sentence.

Which to use

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

#26
“foi” frequency rank
#16,068
“fun” frequency rank
16094
confusion score

Side-by-Side Comparison

Feature foi fun
Definition terceira pessoa do singular do pretérito perfeito do indicativo do verbo ser divertido

Where the eye mixes foi and fun

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

3 ch
foi
3 ch
fun

Visual trap between foi and fun

These two trip readers on the page rather than in the ear: foi is /ˈfoj/ while fun is /fʌn/. 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 (verb vs adjective), which is usually the fastest check. Our composite confusion score for this pair is 16094, derived from the frequency rank of both members and their visual similarity.

foi is recorded at frequency rank #26, classified as averb, pronounced /ˈfoj/. fun is at rank #16,068, tagged as anadj, 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 16094, this pair ranks #55,528 of 75,631 scored Portuguese confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of foi vs fun

Shared letters: f. Private to "foi": io. Private to "fun": nu.

"foi" · 3 letters · shape CVV  ·  "fun" · 3 letters · shape CVC

Frequently Asked Questions

Is swapping "foi" for "fun" ever safe?
No - they are not even the same part of speech. "foi" is a verb and "fun" an adjective, so a sentence built for one is usually ungrammatical with the other.
In ordinary Portuguese text, does "foi" or "fun" show up more?
"foi" is the more common of the two: it sits at frequency rank #26 in our Portuguese list, against #16,068 for "fun". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

What to do next

Eye-level mix-up between "foi" and "fun" is sorted above. Next: full entries or other pairs that share a letter shape.

  • Full dictionary entry for "foi" 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 #55,528 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
  • "foi" and "fun" also get mixed up with nearby pairs, the highest-scored neighbour is "fern vs fun". Nearby pair

Confusion rank #55,528 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list