Word Origin & History
O.E. caru, cearu "sorrow, anxiety, grief," also "serious mental attention," from P.Gmc. *karo, from PIE base *gar- "cry out, scream." Sense of "charge, oversight, protection" is c.1400. The verb is O.E. carian, cearian "to feel concern or interest," from P.Gmc. *karojanan. Phrase couldn't care less is
from 1946; could care less in the same sense (with an understood negative) is 1966. Care figures in many "similies of indifference" in the form don't care a _____, with the blank filled by fig, pin, button, cent, straw, rush, point, farthing, snap, etc.
1550s (n.) action of care
(q.v.). As a pp. adj., "compassionate," attested from 1966.