must
muhst
Must (verb) means used to say that something is required or necessary. Example: “You must show your passport before boarding.”
verb
1
Used to say that something is required or necessary.
"You must show your passport before boarding."
"Visitors must wear a name badge at all times inside the building."
"Passengers must switch off their phones during take-off."
2
Used to say that something is very likely or almost certainly true.
"She hasn't answered her phone all day — she must be travelling."
"You must be tired after such a long journey."
"That must be the postman, because the dog is barking."
noun
1
Something that is essential or highly recommended.
"Good walking shoes are an absolute must for this hike."
"A warm coat is a must if you visit in winter."
"This museum is a must for anyone interested in old ships."
How to use must
Learner’s notesIn plain EnglishExpresses obligation ("you must go") or strong likelihood ("that must be true"), or as a noun, something essential.
Common pairings
a must-have
must-see
you must be joking
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Word forms
- Plural
- musts
- Third person singular
- mote, musts
- Plural verb form
- mote
- Past tense
- musted
- Archaic forms
- motest
Fill the gap
Can you complete this real example?
You _____ show your passport before boarding.
Etymology
From Old English moste, the past tense of a verb meaning "to be allowed or obliged to."
Synonyms
View more →
have to
need to
have got to
be required to
be obliged to
be compelled to
moldiness
mustiness
Related words
Rhymes for must
See all rhymes for must →Frequently asked questions
What does “must” mean?
The word “must” means used to say that something is required or necessary. In plain terms, expresses obligation ("you must go") or strong likelihood ("that must be true"), or as a noun, something essential.
How do you pronounce “must”?
“Must” is pronounced muhst (/məst/ in IPA).
How do you use “must” in a sentence?
Here is “must” used in a sentence: “You must show your passport before boarding.”
What part of speech is “must”?
Depending on how it is used, “must” can be a verb and a noun.
Where does the word “must” come from?
The word “must” comes from Old English. From Old English moste, the past tense of a verb meaning "to be allowed or obliged to.".
Is “must” a common word?
“Must” is a very common word in modern English, usually learned at around the A1 level.
How many meanings does “must” have?
“Must” has 3 distinct senses listed in this dictionary. The most common is: used to say that something is required or necessary.
What is the difference between 'must' and 'have to'?
Both express necessity, but "must" often comes from the speaker's own sense of obligation or a strong personal view, as in "I must call her." "Have to" usually points to an outside rule or circumstance, as in "I have to wear a uniform." In everyday speech they overlap, but "must" feels more urgent and personal.
What is the difference between 'must' and 'should'?
"Must" states that something is necessary or required, with no real choice. "Should" gives advice or a recommendation, leaving room to decide otherwise. "You must stop at a red light" is a rule; "you should rest more" is guidance. Must carries obligation; should carries suggestion, so must is far stronger.
What is the difference between 'must not' and 'don't have to'?
They mean opposite things. "Must not" is a prohibition; it is forbidden, so "you must not walk on the grass" bans it entirely. "Don't have to" means there is no obligation, but you may if you wish, so "you don't have to come" leaves it open. Confusing the two can completely reverse your meaning.
What does 'must' mean in a sentence like 'he must be tired'?
Here "must" does not express obligation but a confident guess, or deduction. Seeing the evidence, the speaker concludes something is almost certainly true, so "he must be tired" means "I'm sure he is tired." This use expresses strong probability based on reasoning, rather than a rule or a requirement to act.
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