obscure, cloaked, unseen, unknown, vague, murky... as Cogito said, it greatly depends on the context.
Intents are often veiled Definition of VEILED 1a : having or wearing a veil or a concealing cover b : characterized by a softening tonal distortion 2: obscured as if by a veil : disguised messages often ambiguous    1. open to or having several possible meanings or interpretations; equivocal: an ambiguous answer. 2. Linguistics . (of an expression) exhibiting constructional homonymity; having two or more structural descriptions, as the sequence Flying planes can be dangerous. 3. of doubtful or uncertain nature; difficult to comprehend, distinguish, or classify: a rock of ambiguous character. 4. lacking clearness or definiteness; obscure; indistinct: an ambiguous shape; an ambiguous future. Definition of DUPLICITY 1: contradictory doubleness of thought, speech, or action; especially : the belying of one's true intentions by deceptive words or action 2: the quality or state of being double or twofold