Words beginning wth M and ending with ING:
It could be malingering.
nothing unless you want a word that ends with an -ing sound
Matching
kim, kilm,kom
beam brim boom
isotherm, idealism
monkfish
Unmask? Something un-m..
mate ?
Broom, bloom, bosom.
militant, murkiest, movement
The word you're looking for is monopoly.