| vague(adjective, clear, rough, anxious, definite) |
| indefinite(adjective, rough, strange, vague, mysterious) |
| remote(adjective, obscure, experience, new, different) |
| unapparent |
| unascertained(adjective, obscure, strange, mysterious, indefinite) |
| undefined(adjective, vague, general, unclear, ambiguous) |
| undisclosed(adjective, obscure, dark, hidden, concealed) |
| unimportant(adjective, humble, distant, minor, remote) |
| unknowable(obscure, dark, superior, strange, mysterious) |
| unknown quantity(noun, expression, idiom, doubt, doubtfulness) |
| untold(adjective, obscure, strange, mysterious, indefinite) |
| dishonorable |
| incalculable(adjective, ineffable, inexpressible, indescribable) |
| anon |
| covert(strange, secret, hidden, curious, concealed) |
| extraneous(adjective, experience, distant, different, unfamiliar) |
| inconspicuous(adjective, humble, distant, minor, remote) |
| indeterminate(adjective, rough, anxious, unsettled, worried) |
| interloper(noun, alien, visitor, foreigner) |
| invisible(obscure, dark, superior, deep, mysterious) |