Old English cearig "sorrowful, full of care," the adjective from care (n.), q.v. Sense evolved 16c. from "full of care" to "careful." Compare the sense evolution of careful. Meaning "sparing, frugal" is from 1560s. Cognate with Old Saxon carag, Old High German charag "full of sorrow, trouble, or care." Related: Charily; chariness.