must vs requirement

must and requirement both are nouns.

Word	Noun	Adjective	Verb	Adverb
must	Yes	Yes	No	No
requirement	Yes	No	No	No

As nouns, requirement is a hypernym of must; that is, requirement is a word with a broader meaning than must:

Other hypernyms of must include essential, necessary, necessity, requisite.

must (noun)	requirement (noun)
the quality of smelling or tasting old or stale or mouldy	something that is required in advance
grape juice before or during fermentation	required activity
a necessary or essential thing	anything indispensable

must (adjective)	requirement (adjective)
highly recommended