| pansophic(sound, knowledgeable, cultured, educated, erudite) |
| pedant |
| polymath(sound, knowledgeable, cultured, educated, erudite) |
| private(adjective, obscure, secret, unknown, hidden) |
| problematic(adjective, hard, fancy, difficult, complex) |
| rich |
| sapient(sound, knowledgeable, cultured, educated, erudite) |
| scholarly(obscure, complex, deep, thoughtful, modern) |
| secluded(obscure, dark, secret, unknown, hidden) |
| sensitive(sharp, exact, discriminating) |
| sequestered(obscure, dark, secret, unknown, hidden) |
| serious(intense, heavy, deep, fierce, thoughtful) |
| strong |
| studious(knowledgeable, cultured, educated, erudite, enlightened) |
| tangled(adjective, hard, obscure, difficult, complex) |
| under cover(expression, obscure, dark, unseen) |
| under wraps(expression, clandestine, underground, undisclosed) |
| undercover(secret, unknown, hidden, underground, concealed) |
| underground(obscure, secret, unknown, hidden, concealed) |
| unintelligible(adjective, hard, obscure, difficult, delicate) |