the sterile offspring of a mating between a female horse and an ass: compare hinny1
a sterile hybrid animal or plant, esp a cross between a canary and another bird
a stubborn person
a machine for producing simultaneously drawing and twisting fibre into yarn or thread and winding it on spindles
informal a courier transporting illegal drugs or laundered money
[Old English mūl, reinforced in Middle English by Old French mul, from Latin mulus]