# mustn't

> English word · Verb · IPA /ˈmʌs.n̩t/ · frequency rank #34,605

## Definitions
1. must not (negative auxiliary); used to indicate that something is forbidden or, in a tag question, that something is not necessary.

## Etymology
must + -n't

## Common misspellings (11)
`mmustn't`, `msutn't`, `musnt't`, `musstn't`, `must'nt`, `mustn'tt`, `mustnn't`, `mustnt'`, `musttn't`, `mutsn't`, `umstn't`

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