Lacking spirit or desire
dull, stupid, spiritless, inattentive, drowsy, sleepy, languid, dreamy, thoughtless, indolent, heedless, lifeless, abstracted, absent, laggard, faint, lacking zest, slack, mopish, supine, inanimate, phlegmatic, dormant, insouciant, lukewarm, nonchalant, careless, torpid, sluggish, leaden, heavy, lethargic, bored, uninterested, languorous, neutral, lackadaisical, enervated, apathetic, easy-going; see also indifferent 1, unconcerned.
Antonyms active*, vivacious, vigorous.