# undo vs union

> English confusable word pair

## The two words

### undo
*verb · IPA /ʌnˈduː/ · frequency rank #13,631*
To reverse the effects of an action.

### union
*noun · IPA /ˈjuː.njən/ · frequency rank #890*
The act of uniting or joining two or more things into one.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/vs/undo-vs-union