key vs qui, What's the Difference?

Which to use

“key” is an adjective and “qui” is a pronoun - they look or sound alike but fill different roles in a sentence.

#10,384
“key” frequency rank: #9,094
“qui” frequency rank: 19478
confusion score

Side-by-Side Comparison

Feature	key	qui
Definition	indispensável	que relativo; o qual, a qual, os quais, as quais

Where the eye mixes key and qui

Muted = shared; highlighted = the visual trap. No shared run - shape, not overlap, is the trap.

3 ch

key

3 ch

qui

Why the eye confuses key with qui

These two trip readers on the page rather than in the ear: key is /kiː/ while qui is /Ki/. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 3 positions, and the parts of speech differ too (adjective vs pronoun), which is usually the fastest check. Our composite confusion score for this pair is 19478, derived from the frequency rank of both members and their visual similarity.

key is recorded at frequency rank #10,384, classified as anadj, pronounced /kiː/. qui is at rank #9,094, tagged as apron, pronounced /Ki/.

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 19478, this pair ranks #51,224 of 75,631 scored Portuguese confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of key vs qui

Shared letters: none. Private to "key": eky. Private to "qui": iqu.

"key" · 3 letters · shape CVV · "qui" · 3 letters · shape CVV

Frequently Asked Questions

Is swapping "key" for "qui" ever safe?

No - they are not even the same part of speech. "key" is an adjective and "qui" a pronoun, so a sentence built for one is usually ungrammatical with the other.

Which is more common, "key" or "qui"?

"qui" is the more common of the two: it sits at frequency rank #9,094 in our Portuguese list, against #10,384 for "key". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.

Full dictionary entry for "key" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "qui" - compare definitions side by side with the headword page. Word entry
This pair ranks #51,224 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"key" and "qui" also get mixed up with nearby pairs, the highest-scored neighbour is "qui vs quit". Nearby pair

Confusion rank #51,224 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.