Etymology

From a conflation of "mummer"; one that keeps silent, from mum, ultimately of imitative origin, and Old French momeor, from mommer ‎(“to wear a mask”), from momon ‎(“mask”). Compare German Mumme ‎(“mask”), 16th Century German mummen ‎(“to disguise oneself”), Middle Dutch mommen, mummen ‎(“to go about in a mask, to disguise”), Middle Low Saxon mommen ‎(“to wear a mask, to disguise”), Dutch mom ‎(“mask”) and to mask as well as Spanish momo ‎(“grimace”).

Perhaps both of the conflated terms are from the same ultimate root, as note Middle Low Saxon mummen ‎(“to speak indistinctly, to disguise oneself”), Dutch mommen ‎(“to speak indistinctly”), German mummen ‎(“to speak indistinctly”), mump ‎(“to grimace, to mumble”).

Pronunciation

• (Received Pronunciation) IPA^(key): /ˈmʌm.ə/
• (Received Pronunciation) IPA^(key): /ˈmʌm.ɚ/