| intelligent(adjective, characteristic, sharp, smart, bright) |
| intent(adjective, activity, strong, excite, intense) |
| intricate(adjective, hard, evil, obscure, heavy) |
| mystifying(adjective, hard, evil, delicate, loose) |
| rapt(adjective, activity, excite, informal, intense) |
| sagacious(adjective, sharp, smart, bright, intelligent) |
| sonorous(adjective, strong, intense, big, heavy) |
| sound(noun, verb, adjective, good, reasonable) |
| trench |
| tricky(adjective, sharp, intelligent, cunning, clever) |
| wily(adjective, sharp, intelligent, cunning, clever) |
| complex(adjective, hard, obscure, delicate, meaning) |
| concentrated(adjective, activity, set, strong, solid) |
| consuming(adjective, intense, captivating, spellbinding, hypnotic) |
| contralto(adjective, intense, sounds, alto, throaty) |
| deeply |
| detailed(adjective, intimate, secret, private, thorough) |
| engaged(adjective, activity, intense, full, fixed) |
| low-pitched(adjective, weak, low, intense, pale) |
| preoccupied(adjective, activity, set, excite, intense) |