ui vs um, What's the Difference?

Which to use

“ui” is an intj and “um” is an article - they look or sound alike but fill different roles in a sentence.

#19,875
“ui” frequency rank: #12
“um” frequency rank: 19887
confusion score

Side-by-Side Comparison

Feature	ui	um
Definition	exprime surpresa, admiração, repugnância	qualquer

Where the eye mixes ui and um

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

2 ch

Why the eye confuses ui with um

These two trip readers on the page rather than in the ear: ui is /ˈuj/ while um is /ũw/. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - i in “ui” becomes m in “um”, and the parts of speech differ too (intj vs article), which is usually the fastest check. Our composite confusion score for this pair is 19887, derived from the frequency rank of both members and their visual similarity.

ui is recorded at frequency rank #19,875, classified as anintj, pronounced /ˈuj/. um is at rank #12, tagged as anarticle, pronounced /ũw/.

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 19887, this pair ranks #50,746 of 75,631 scored Portuguese confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of ui vs um

Shared letters: u. Private to "ui": i. Private to "um": m.

"ui" · 2 letters · shape VV · "um" · 2 letters · shape VC

Frequently Asked Questions

Is swapping "ui" for "um" ever safe?

No - they are not even the same part of speech. "ui" is an intj and "um" an article, so a sentence built for one is usually ungrammatical with the other.

In ordinary Portuguese text, does "ui" or "um" show up more?

"um" is the more common of the two: it sits at frequency rank #12 in our Portuguese list, against #19,875 for "ui". 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 "ui" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "um" - compare definitions side by side with the headword page. Word entry
This pair ranks #50,746 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"ui" and "um" also get mixed up with nearby pairs, the highest-scored neighbour is "ú vs ui". Nearby pair

Confusion rank #50,746 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.