lummox

noun

Etymology: Unknown. First attested in 1825 in East Anglian slang. Perhaps from "dumb ox", influenced by lumbering; or from or cognate to dialectal verb lummock (“move about heavily or clumsily”), itself a word of uncertain origin.

1. A clumsy, stupid person; an awkward bungler.

   “You've broken the plates, you great lummox!”

   “As a rule, a knight is a lummux, and sometimes even a labrick, and hence open to pretty poor arguments when they come glibly from a superstition-monger, but even he could see the practical side of a thing once in a while; […]”