(mum) v.i. mummed, mum·ming Obs.
To be silent.
—adjective Silent; saying nothing.
—noun Silence: Mum's the word.
—interj. Hush! Be quiet! [Imit.]

(mum) v.i. mummed, mum·ming
To play or act in a mask, as at Christmas; be a mummer. Also mumm. [<MUM¹. Cf. MDu. mommen mask, OF momer act in a dumb show.]

(mum) noun
A strong sweet beer, first brewed in Germany by Christian Mumme, 1492.

(mum)
Corruption of MADAM, MA'AM.

(mum) noun Colloq.
A chrysanthemum.