| under wraps(expression, adjective, clandestine, underground, sneaky) |
| undercover(adjective, clandestine, underground, undisclosed, sneaky) |
| underhanded(adjective, clandestine, underground, undisclosed, sneaky) |
| unenlightened(adjective, obscure, unknown, clandestine, underground) |
| unfrequented(adjective, obscure, unknown, clandestine, underground) |
| united |
| uniting |
| unjust(adjective, sympathetic, interested, prejudiced, opinionated) |
| unpublished(adjective, obscure, unknown, clandestine, underground) |
| unreasoning(adjective, sympathetic, collateral, interested, prejudiced) |
| unseen(adjective, obscure, unknown, clandestine, underground) |
| warped(adjective, sympathetic, interested, prejudiced, opinionated) |
| wedded |
| zealous(adjective, sympathetic, interested, prejudiced, opinionated) |
| Janus-faced |
| abstruse(adjective, obscure, unknown, clandestine, underground) |
| adjunctive(adjective, collateral, subsidiary, subservient, subalternate) |
| adjuvant(adjective, collateral, subsidiary, subservient, subalternate) |
| adventurous |
| ambiguous(adjective, obscure, unknown, clandestine, underground) |