abrupt [M16th] The Latin source of this word was abrumpere ‘broken off, steep’, from rumpere ‘to break’. In the past, abrupt could be used as a noun meaning ‘abyss’ (Milton, Paradise Lost: ‘Upborn with indefatigable wings Over the vast abrupt’). It had developed the modern senses of ‘sudden, unexpected’ used to describe someone’s manner by the late 16th century.