Mug/mugger

Mug is an old word of Scandinavian origin for an earthenware container and as a drinking vessel dates from the 1600s. Mug has been slang for face since the early 18th century when mugs, such as Toby jugs, had foolish or grotesque faces on them. Mug, as in fool, dupe or stupid person is slang from the mid-19th century and the OED maintains is possibly connected to the preceding meaning. The phrase, ‘a mug’s game’ meaning a foolish and unprofitable pastime derives from this meaning. Mug, as in to ‘mug up’ on a subject or topic, meaning to read up or study hard, also dates from the mid-19th century and its origin is unknown, but could possibly derive from the strained expression on a person’s face when so engaged. Mug as in violent street crime, and mugger one who commits such crime, dates from the mid-19th century.