introspective (adj.)
- absorbed
- abstracted
- cogitative
- cognitive
- conceptive
- conceptual
- contemplative
- deliberative
- engrossed
- meditative
- mental
- musing
- noetic
- occupied
- pensive
- pondering
- prehensive
- preoccupied
- rapt
- reflecting
- reflective
- ruminant
- ruminative
- serious
- sober
- speculative
- thinking
- thought
- thoughtful
- wistful
