sleep [OE] A word first recorded around ad 800. The modern-sounding phrase sleep with, meaning ‘to have sex with’, is almost as old, and was used by the Anglo-Saxons.

The modern form of the proverb let sleeping dogs lie appears first in Sir Walter Scott’s 1824 novel Redgauntlet. Long before that, in the 14th century, Geoffrey Chaucer advised in Troilus and Criseyde that ‘it is not good a sleeping hound to wake’. To sleep with the fishes for to die was popularized by the 1972 film The Godfather but had been in use since the mid 19th century.