Synonyms and related words :
cogitative, concentrating, concentrative, conceptive, conceptual, conceptualized, contemplating, contemplative, deliberating, deliberative, excogitating, ideative, introspective, meditating, meditative, mental, museful, musing, noetic, pensive, pondering, prehensive, reflecting, reflective, ruminant, ruminating, ruminative, serious, sober, speculative, thinking, thought, thoughtful, wistful,