carelessness

Etymology

From Middle English *carelesnes, *carlesnesse, from Old English carlēasnes (“freedom from care, security, carelessness”), equivalent to careless + -ness.

noun

1. Lack of care; the state or quality of being careless.
   This accident was caused by carelessness.
   There were, however, 34 deaths among passengers in movement accidents, due mainly to misadventure and carelessness when entering and leaving trains in motion, falling off platforms and out of carriages, and opening and closing carriage doors. 1960 December, “Talking of Trains: B.R. safety in 1959”, in Trains Illustrated, page 708