What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
The past imperfect tense.
Early 16th century (in an earlier sense). From preter + imperfect, after post-classical Latin praeteritum imperfectum, lit. ‘uncompleted past’ (3rd cent.) Compare preterperfect, preterperfect, preterpluperfect, preterpluperfect.