WordNet sense 1 (marked by careful consideration or reflection):

deliberate, deliberate

WordNet sense 2 (persistently or morbidly thoughtful):

contemplative, musing, pensive, reflective

WordNet sense 3 (deeply absorbed in thought):

preoccupied

WordNet sense 4 (acting with or showing thought and good sense):

serious-minded

WordNet sense 5 (concerned with work or important matters rather than play or trivialities):

serious

WordNet sense 6 (showing intellectual penetration or emotional depths; from the depths of your being):

profound

WordNet sense 7 (taking heed; giving close and thoughtful attention):

attentive, heedful, paying attention

WordNet sense 8 (showing concern for the rights and feelings of others):

considerate