undovsunoWhich spelling fits?

Quick tell: undo is a verb, uno is an intj, so they fill different roles in a sentence.

Which to use

“undo” is a verb and “uno” is an intj - they look or sound alike but fill different roles in a sentence.

#13,631
“undo” frequency rank
#20,255
“uno” frequency rank
33886
confusion score

Side-by-Side Comparison

Feature undo uno
Definition To reverse the effects of an action. A term said when the number of cards in player’s hand is reduced to one. If another player says this before the one whose hand contains only one card, the player who failed to say 'uno' must draw two cards.

Where the eye mixes undo and uno

Muted = shared; highlighted = the visual trap. They share 3 letters in sequence.

4 ch
undo
3 ch
uno

Why the eye confuses undo with uno

These two trip readers on the page rather than in the ear: undo is /ʌnˈduː/ while uno is /ˈuː.noʊ/. 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 (verb vs intj), which is usually the fastest check. Our composite confusion score for this pair is 33886, derived from the frequency rank of both members and their visual similarity.

undo is recorded at frequency rank #13,631, classified as averb, pronounced /ʌnˈduː/. uno is at rank #20,255, tagged as anintj, pronounced /ˈuː.noʊ/.

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 33886, this pair ranks #325,513 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of undo vs uno

Shared letters: nou. Private to "undo": d. Private to "uno": -.

"undo" · 4 letters · shape VCCV  ·  "uno" · 3 letters · shape VCV

Known mistypes of this pair

  • undonudo · udno · unddo · unndo · unod

Frequently Asked Questions

Is swapping "undo" for "uno" ever safe?
No - they are not even the same part of speech. "undo" is a verb and "uno" an intj, so a sentence built for one is usually ungrammatical with the other.
In ordinary English text, does "undo" or "uno" show up more?
"undo" is the more common of the two: it sits at frequency rank #13,631 in our English list, against #20,255 for "uno". 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 "undo" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "uno" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #325,513 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "undo" and "uno" also get mixed up with nearby pairs, the highest-scored neighbour is "UAS vs uno". 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 #325,513 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