Synonyms and related words :
absent, absentminded, absorbed, abstracted, atrabiliar, atrabilious, bemused, blue, brooding, castle-building, cogitative, cognitive, concentrating, concentrative, conceptive, conceptual, conceptualized, contemplating, contemplative, daydreaming, daydreamy, deliberating, deliberative, dreaming, dreamy, drowsing, ecstatic, elsewhere, engrossed, excogitating, faraway, funky, grave, half-awake, ideative, in a reverie, in a trance, in the clouds, introspective, lost, lost in thought, meditating, meditative, melancholic, melancholy, mental, mooning, moonraking, museful, musing, napping, nodding, noetic, oblivious, pipe-dreaming, pondering, prehensive, preoccupied, rapt, reflecting, reflective, ruminant, ruminating, ruminative, sad, saddened, serious, sober, somewhere else, speculative, stargazing, taken up, thinking, thought, thoughtful, transported, tristful, unconscious, wistful, withdrawn, woolgathering, wrapped in thought