must

Multiple Entries:
  must    must-  

Concise Oxford English Dictionary © 2008 Oxford University Press:
must1

▶modal verb (past had to or in reported speech must)

• 1 be obliged to; should.

  ■ expressing insistence.

• 2 expressing an opinion about something that is very likely.

▶noun informal something that should not be overlooked or missed.

– origin OE mōste, past tense of mōt ‘may’, of Gmc origin.

Concise Oxford English Dictionary © 2008 Oxford University Press:
must2

▶noun grape juice before or during fermentation.

– origin OE, from L. mustum, neut. (used as n.) of mustus ‘new’.

Concise Oxford English Dictionary © 2008 Oxford University Press:
must3

▶noun mustiness or mould.

– origin C17: back-form. from musty.

Concise Oxford English Dictionary © 2008 Oxford University Press:
must4 (also musth)

▶noun the frenzied state of a rutting male elephant or camel.

– origin C19: via Urdu from Pers. mast ‘intoxicated’.

Concise Oxford English Dictionary © 2008 Oxford University Press:
must-

▶combining form used to form adjectives denoting things that are essential or highly recommended: must-have | a must-read book.