Silent; not speaking. The citizens are mum; say not a word.

As an exclamation or command, be silent; hush. Mum the, and no more proceed.

AS a noun.

A species of malt liquor much used in Germany. It is made of the malt of wheat, seven bushels, with one bushel of oat meal and a bushel of ground beans, or in the same proportion. This is brewed with 63 gallons of water, and boiled till one third is evaporated.