Synonyms and related words :
bright, cerebral, cogitative, cognitive, concentrating, concentrative, conceptive, conceptual, conceptualized, contemplating, contemplative, deliberating, deliberative, discursive, endopsychic, excogitating, ideational, ideative, intellectual, intelligent, internal, introspective, knowing, meditating, meditative, mental, museful, musing, noological, not so dumb, pensive, phrenic, pondering, prehensive, psychic, psychologic, rational, reasonable, reasoning, reflecting, reflective, ruminant, ruminating, ruminative, sane, sensible, serious, sober, sophic, speculative, spiritual, strong-minded, subjective, thinking, thought, thoughtful, understanding, wistful