A large cup for beverages, usually having a handle and used without a saucer.A mug

(slang, often derogatory) The face.

(slang, derogatory) A gullible or easily-cheated person.

(UK, Australia, derogatory, slang) A stupid or contemptible person.

(slang) A criminal.

(slang, African-American Vernacular) Motherfucker (usually in similes, e.g. "like a mug" or "as a mug")

(transitive) To assault for the purpose of robbery.

(intransitive) To exaggerate a facial expression for communicative emphasis; to make a face, to pose, as for photographs or in a performance, in an exaggerated or affected manner.

(transitive) To photograph for identification; to take a mug shot.

(UK, Australia, Singapore, slang) To learn or review a subject as much as possible in a short time; cram.

(Bermuda, slang) Uninteresting or unpleasant.