Not clearly or explicitly defined.
Not easy to see or read; indecipherable or unreadable.
Ambiguous; liable to more than one interpretation.
Not having a clear idea; uncertain.
To undo the process of clearing.
Not known; unidentified; not well known.
A variable (usually x, y or z) whose value is to be found.
A person of no identity; a nonentity
Any thing, place, or situation about which nothing is known; an unknown fact or piece of information.