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1. Be compelled, be necessary, have to, ought to
   "I must take the test before I can drive"; "you really must tidy the room some time"; "to pass the exam you must work hard"

1. Highly recommended
   "a book that is must reading"

1. A necessary or essential thing
   "seat belts are an absolute must"
    
2. Grape juice before or during fermentation
    
3. The quality of smelling or tasting old or stale or mouldy
   - mustiness, moldiness [N. Amer], mouldiness [Brit, Cdn]
    
4. An annual phase of heightened sexual excitement in the males of certain large mammals (especially elephants); is associated with discharge from a gland between the eye and ear
   - musth

Sounds like: muse, mews, Meuse, must, musth, mu

Derived forms: musts, musted, musting

See also: essential

Type of: essential, grape juice, necessary, necessity, phase, requirement, requisite, stage, staleness

Encyclopedia: Must, Richard