n. 1 lack of energy or vitality; a torpid, inert, or apathetic state. 2 Med. morbid drowsiness or prolonged and unnatural sleep. lethargic adj. lethargically adv.
[ ME f. OF litargie f. LL lethargia f. Gk lethargia f. lethargos forgetful f. leth-, lanthanomai forget ]