(mug) noun
1. A drinking cup, usually cylindrical, with a handle and no lip.
2. That which is contained in a mug. [Cf. Sw. mugg, Norw. mugga]

(mug) Slang noun
1. The human face or mouth.
2. A grimace.
3. A photograph of the face of a suspect: also mug shot.
4. A criminal.
—v. mugged, mug·ging v.t.
1. To photograph (someone), especially for official purposes.
2. To assault, usually with the intent to rob.
—v.i.
3. To make faces; grimace. [<MUG¹; prob. from the fact that drinking mugs were often shaped to resemble a face]
—mug′ger noun