(present & past all persons must)
Etymology: Middle English moste, from Old English mōste, past indicative & subjunctive of mōtan to be allowed to, have to; akin to Old High German muozan to be allowed to, have to
Date: before 12th century
a. be commanded or requested to <you must stop> b. be urged to ; ought by all means to <you must read that book> 2. be compelled by physical necessity to <one must eat to live> ; be required by immediate or future need or purpose to <we must hurry to catch the bus> 3. a. be obliged to ; be compelled by social considerations to <I must say you're looking well> b. be required by law, custom, or moral conscience to <we must obey the rules> c. be determined to <if you must go at least wait for me> d. be unreasonably or perversely compelled to <why must you argue> 4. be logically inferred or supposed to <it must be time> 5. be compelled by fate or by natural law to <what must be will be> 6. was or were presumably certain to ; was or were bound to <if he did it she must have known> 7. dialect may, shall — used chiefly in questions intransitive verb archaic to be obliged to go <I must to Coventry — Shakespeare> II. noun Date: 1616 1. an imperative need or duty ; requirement 2. an indispensable item ; essential <exercise is a must> III. noun Etymology: Middle English, from Old English, from Latin mustum Date: before 12th century the expressed juice of fruit and especially grapes before and during fermentation; also the pulp and skins of the crushed grapes IV. noun Etymology: Middle English (Scots) moist, from Middle French must, alteration of musc musk Date: 15th century 1. musk 2. mold, mustiness
New Collegiate Dictionary. 2001.