beetle-browed

This expression is very old - first recorded in William Langland's The vision of William concerning Piers Plowman, 1362: "He was bitel-brouwed..."What was meant by the term at that date is a matter of conjecture. In the 14th century there were two meanings of the noun beetle, or bitel as it was then spelled: either the insect, or a heavy-headed wooden implement used for driving in pegs etc, i.e. a mallet.