| bemusement |
| blind(adjective, careless, indifferent, apathetic, distracted) |
| bored(adjective, careless, indifferent, apathetic, distracted) |
| brainstorming |
| brainwork(noun, understanding, attention, thought, hope) |
| brainy(adjective, reasonable, keen, deep, rational) |
| brood |
| careless(noun, adjective, indifferent, apathetic, distracted) |
| castle in the air(noun, expression, idiom, trip, fancy) |
| castles in the air(noun, expression, idiom, fantasy, dream) |
| cerebral(adjective, reasonable, keen, deep, rational) |
| chimerical(excellent, gentle, marvelous, vague, dreamy) |
| clear(adjective, feature, characteristic, focus) |
| close study |
| clue(noun, concept, understanding, grasp, command) |
| cognition(noun, concept, understanding, philosophy, grasp) |
| cognitive |
| communing(noun, verb, concept, understanding, grasp) |
| comprehension(noun, concept, understanding, grasp, command) |
| conceit(noun, understanding, grasp, command, impression) |