Definition of must

• v. i. / auxiliary - To be obliged; to be necessitated; -- expressing either physical or moral necessity; as, a man must eat for nourishment; we must submit to the laws.
• v. i. / auxiliary - To be morally required; to be necessary or essential to a certain quality, character, end, or result; as, he must reconsider the matter; he must have been insane.
• n. - The expressed juice of the grape, or other fruit, before fermentation.
• n. - Mustiness.
• v. t. & i. - To make musty; to become musty.