Meaning

• A large cup for hot liquids, usually having a handle and used without a saucer.

• The face, often used deprecatingly.

  "What an ugly mug."

• A gullible or easily-cheated person.

  "He's a gullible mug – he believed her again."

• A stupid or contemptible person.

Meaning

• To strike in the face.

• To assault for the purpose of robbery.

• 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.

  "The children weren't interested in sitting still for a serious photo; they mugged for the camera."

• To photograph for identification; to take a mug shot.

• To learn or review a subject as much as possible in a short time; cram.

Meaning

• Easily fooled, gullible.