mustn't

/ˈmʌs.n̩t/

//ˈmʌs.n̩t// verb

By · According to Wiktionary data (CC BY-SA) ·

"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
4,057
“M” headwords
11
tracked misspellings

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - must not (negative auxiliary); used to indicate that something is forbidden or, in a tag question, that something is not necessary.

Corpus desk

Index EN-mustn-t · mustn't · English

mustn't · rank #34,605 · 11 variants · 0 confusables

  • FREQ-MID #34,605
  • LEN-LONG 7 letters
  • VOW-1 1 vowel
  • CONFUS-0 No pairs
  • VAR-MID 11 variants
  • BOOK-MID 4,057
  • PHOTO-FINISH multivariate

Nearest frequency peer: multivariate (-1 rank slots)

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Rank peers near misspelling magnet “mustn't”

Same rarity band: useful when a typo lands on a peer headword

corpus weight

What this shows “mustn't” sits among these FrequencyWords peers; misspelling depth is tracked separately in the edit-distance chart.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for mustn't
PropertyValue
Headwordmustn't
LanguageEnglish
Part of speechVerb
IPA/ˈmʌs.n̩t/
Letters7
Frequency rank#34,605
Misspellings tracked11
Confusable pairs0
SourceWiktionary (kaikki.org)

Frequency seat of misspelling magnet “mustn't”

This scale runs from the tiny cluster of words that carry ordinary speech (left) to the long tail of words almost nobody reaches for (right).mustn'tlands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Same rarity band neighbours include “multivariate” (#34,604), “nadir” (#34,606), “Mukherjee” (#34,603). Among 4,057 “M” headwords, “mustn't” is #34,605. Source: FrequencyWords open word-frequency list.

A misspelling magnet

The generator records 11 spelling variants around mustn't (IPA /ˈmʌs.n̩t/), averb. Corpus frequency is #34,605 among 4,057 “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

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

Recorded use

Wiktionary examples

These source excerpts show how mustn't appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. You mustn't blame yourself for this tragedy.
  2. We must go, mustn't we?

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.

mmustn't1msutn't2musnt't2musstn't1must'nt2mustn'tt1mustnn't1mustnt'2
Edit distance from "mustn't"

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"?
"mustn't" is spelled M-U-S-T-N-'-T. The IPA pronunciation is /ˈmʌs.n̩t/.
What does "mustn't" mean?
As a verb, "mustn't" means: must not (negative auxiliary); used to indicate that something is forbidden or, in a tag question, that something is not necessary.
What are common misspellings of "mustn't"?
Common misspellings include "mmustn't", "msutn't", "musnt't", "musstn't", "must'nt". The correct spelling is "mustn't".
How do you pronounce "mustn't"?
The IPA (International Phonetic Alphabet) transcription for "mustn't" is /ˈmʌs.n̩t/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "mustn't"?
must + -n't See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "mustn't", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 7 letters (nearest by frequency rank).

notepad#34,611mishaps#34,595outlier#34,621Marston#34,582

Similar misspelling depth

Headwords with a similar count of attested misspellings (11 here; floor ≥5).

outboard11 variantsparsing11 variantshemlock11 variantsheadgear11 variants

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list