Despite its simple spelling, mug can have a lot of meanings. The word first showed up in 1400 as a unit of measurement for salt, and then reappeared in Scottish dialects a century later with the meaning "earthenware bowl". Then the modern definition of "drinking vessel" emerged in the 1560s, probably with some influence from similar Scandinavian words. As you know, mug can also be a colloquial term for "face", and this sense came from the "cup" meaning because of a fad in seventeenth-century England where drinking mugs were made in the shapes of grotesque faces. In the early 1800s, that gave rise to the metonymic verb to mug, meaning "strike someone on the face", which got extended to a broader meaning of "attack" in the 1840s and "attack by robbing" in the 1860s. Mug separately became used to refer to police records of people's faces in the 1870s, and the phrase mug-shot is from the 1950s. So much from just a measurement of salt!
Hello! I'm Adam Aleksic. This year, I graduated from Harvard University with a degree in Government and Linguistics. There, I co-founded the Harvard Undergraduate Linguistics Society and wrote a thesis on Serbo-Croatian language policy, magna cum laude. In addition to etymology, I also really enjoy philosophy, trivia, vexillology, geography, board games, conlanging, art history, and law.