mustn't
/ˈmʌs.n̩t/
"mustn-t" is a 6-letter English headword indexed on PlainSpell.
The verdict
“mustn't” has 11 generated spelling variants in the English index at frequency #34,605. The variants make it a useful spelling check.
- #34,605
- frequency rank, English
- 36,575
- “M” headwords
- 11
- tracked misspellings
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - must not (negative auxiliary); used to indicate that something is forbidden or, in a tag question, that something is not necessary.
| Property | Value |
|---|---|
| Headword | mustn't |
| Language | English |
| Part of speech | Verb |
| IPA | /ˈmʌs.n̩t/ |
| Letters | 7 |
| Frequency rank | #34,605 |
| Misspellings tracked | 11 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “mustn't” sits in English frequency
A misspelling magnet
The generator records 11 spelling variants around mustn't (IPA /ˈmʌs.n̩t/), averb. Corpus frequency is #34,605 among 36,575 “M” headwords. Dominant gloss: "must not (negative auxiliary); used to indicate that something is forbidden or, in a tag question, that something is not necessary.".
Our generated misspelling index lists 11 likely wrong-spelling variants for mustn't, with forms such as "mmustn't", "msutn't", and "musnt't". Every one of these variants traces to a single-character edit -- an added or dropped letter, a swapped consonant, or a vowel swap -- the kind of slip a spell-checker is built to catch. It is not paired with a close-neighbour confusable in our dataset, which tends to mean the word is visually distinctive enough to stand on its own.
Etymologically, the entry records: must + -n't The correct English form is mustn't, spelled M-U-S-T-N-'-T.
Definition
- 1must 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
Also misspelled as:
- mmustn't
- msutn't
- musnt't
- musstn't
- must'nt
- mustn'tt
- mustnn't
- mustnt'
- musttn't
- mutsn't
- umstn't
Misspelling Pattern Breakdown
How far each generated variant is from the correct spelling of mustn't - counted as single-character edits (an insertion, a deletion, or a substituted letter). The larger the bar, the easier the typo is to spot; one-edit slips are the ones that sneak past readers.
Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.
Frequently Asked Questions
How do you spell "mustn't"?
What does "mustn't" mean?
What are common misspellings of "mustn't"?
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Using “mustn't”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is M-U-S-T-N-'-T - every other letter order is a misspelling in standard orthography.
- Say it as /ˈmʌs.n̩t/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
- Browse more English words and confusable pairs in the same reference. English words
Same frequency band
Data Source
Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.