mule

1. The generally sterile male or female hybrid offspring of a male donkey and a female horse.
2. The generally sterile hybrid offspring of any two species of animals.
3. A hybrid plant.
4. A stubborn person.
5. A person paid to smuggle drugs.
6. A coin or medal minted with obverse and reverse designs not normally seen on the same piece, either intentionally or in error.
7. A MMORPG character, or NPC companion in a tabletop RPG, used mainly to store extra inventory for the owner's primary character.
8. Any of a group of cocktails involving ginger ale or ginger beer, citrus juice, and various liquors.
9. A kind of triangular sail for a yacht.
10. A kind of cotton-spinning machine.

verb

To smuggle (illegal drugs).

noun

A shoe that has no fitting or strap around the heel, but which covers the foot.