Mumm v. i. (past & past part. mummed; pres. part. mumming) To sport or make diversion in a mask or disguise; to mask. "With mumming and with masking all around."
... I beg to send you the enclosed statement for the "Story of the Great War". It has been written by Baron Mumm von Schwarzenstein, former Ambassador to Japan, now attached to ... — The Story of the Great War, Volume V (of 8) • Francis J. (Francis Joseph) Reynolds, Allen L. (Allen Leon)