must
n. countablen. something that you really need to have or do because it is very important or popular. You use this when you are giving a strong recommendation.
n. a requirement or a highly recommended item or action. Often used in the phrase 'a must' or 'a must-have' to indicate necessity or high desirability.
A warm coat is a must in this cold weather.
If you visit the city, the local art museum is a must for any history lover.
While the basic software package is functional, the security upgrade is an absolute must for any business handling sensitive client data in the current digital climate.
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.
From Middle English must, from Old English must and Old French must, most, both from Latin mustum.
See musth.
Usually preceded by the indefinite article 'a' and often followed by a prepositional phrase starting with 'for'.