mustn't C2+ Topic:Word Formation & Derivatives US /ˈmʌs.n̩t/ UK /ˈmʌsnt/ See IPA manual Meanings 1 contraction a contraction of must not, used to express prohibition or a strong negative necessity You mustn't open the door until the train stops. 2 contraction used to express a strong negative conclusion or expectation She mustn't have heard the warning. Thesaurus Synonyms 1 contraction · a contraction of must not,... must not 2 contraction · used to express a strong... must not ↔ Opposites must Word family Related forms mustnot Etymology A contraction of must + not. The ending -n't is a reduced form of not, while rapid speech commonly simplifies the consonant cluster so the t of must is weak or absent. Topics Word Formation & Derivatives General Vocabulary External links Google Images Cambridge Dictionary Wiktionary # mustn't **Type:** Word **Level:** C2+ **Part of speech:** contraction **IPA (US):** /ˈmʌs.n̩t/ **IPA (UK):** /ˈmʌsnt/ ## Meanings 1. a contraction of must not, used to express prohibition or a strong negative necessity 2. used to express a strong negative conclusion or expectation ## Examples - You mustn't open the door until the train stops. - She mustn't have heard the warning. ## Synonyms - must not ## Antonyms - must ## Related Forms - must - not ## Etymology A contraction of must + not. The ending -n't is a reduced form of not, while rapid speech commonly simplifies the consonant cluster so the t of must is weak or absent. ## Topics - Word Formation & Derivatives - General Vocabulary markdown