mug

The word 'mug' entered English in the mid-16th century, likely borrowed from Scandinavian languages like Old Norse, where 'mugge' referred to a drinking vessel. The sense of "face," first recorded in the early 18th century, likely arose from the humorous comparison of a person's face to the grotesque faces sometimes molded onto the sides of drinking mugs. From this association with a foolish or exaggerated expression, the word evolved to mean a gullible person, and later, in the 19th century, it developed the verb sense of attacking someone, perhaps from the idea of striking someone in the face or from the criminal slang for a victim.

This word is a simplex form. It is of Scandinavian origin, likely from Old Norse 'mugge' or Swedish 'mugg', meaning a jug or an earthen cup. Its functional role is as a complete lexical root.