Merriam-Webster's Collegiate® Dictionary, 11th Edition
MUM
I. adjective
Etymology: Middle English mom, momme, probably imitative of a sound made with closed lips
Date: 14th century
silent ,
II. intransitive verb (mummed; mumming)
Etymology: Middle English mommen, to mumble, perform (a mummer's play), probably in part from mom, in part from Middle French momer to go masked
Date: 1530
to perform in a pantomime, to go about merrymaking in disguise during festivals,
III. noun
Etymology: German Mumme
Date: 1640
a strong ale or beer, see: mom
V. noun
Date: 1917
chrysanthemum