must.
To do as a requirement; indicates that the sentence subject is required as an imperative or directive to execute the sentence predicate, with failure to do so resulting in a failure or negative consequence.
Meaning & usage
To do as a requirement; indicates that the sentence subject is required as an imperative or directive to execute the sentence predicate, with failure to do so resulting in a failure or negative consequence.
You must arrive in class on time.
This door handle must be rotated fully.
To do with certainty; indicates that the speaker is certain that the subject will have executed the predicate.
If it has rained all day, it must be very wet outside.
Where would you have put the keyring? You couldn’t have lost it again! - I must have, because it's nowhere to be found.
Used to indicate that something is very likely, probable, or certain to be true.
The children must be asleep by now.
There's the doorbell. It must be Dad.
Where this word comes from
From Middle English moste ("must", literally, "had to", the past tense of Middle English moten (“to have to”)), from Old English mōste (“had to”), 1st & 3rd person singular past tense of mōtan (“to be allowed, be able to, have the opportunity to, be compelled to, must, may”), from Proto-Germanic *mōtaną. Cognate with Dutch moest (“had to”), German musste (“had to”), Swedish måste (“must, have to, be obliged to”). More at mote.
Something that is mandatory, required or recommended.
If you're trekking all day, a map is a must.
Where this word comes from
From Middle English moste ("must", literally, "had to", the past tense of Middle English moten (“to have to”)), from Old English mōste (“had to”), 1st & 3rd person singular past tense of mōtan (“to be allowed, be able to, have the opportunity to, be compelled to, must, may”), from Proto-Germanic *mōtaną. Cognate with Dutch moest (“had to”), German musste (“had to”), Swedish måste (“must, have to, be obliged to”). More at mote.
The property of being stale or musty.
Something that exhibits the property of being stale or musty.
Fruit juice that will ferment or has fermented, usually from grapes.
Where this word comes from
From Middle English must, from Old English must and Old French must, most, both from Latin mustum.
To make musty.
To become musty.
Where this word comes from
From Middle English must, from Old English must and Old French must, most, both from Latin mustum.
Alternative spelling of musth.
Where this word comes from
See musth.
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Definitions, grammatical labels, IPA, etymology and examples: Wiktionary contributors, extracted by Kaikki / Wiktextract. Adapted under CC BY-SA 4.0. Selected fields and authored examples are shown; third-party quotations and audio are omitted. See contributor history.
Last enriched 2026-09-10. Definitions are in English. Romanizations are shown when supplied by the source; syllable estimates are omitted for unsupported scripts.