1 equivocal, amphibological, amphibolic or amphibolous; misleading:
If one says 'Taylor saw Tyler drunk', which one was drunk is ambiguous.
2 doubtful, dubious, questionable, obscure, indistinct, unclear, indefinite, indeterminate, uncertain, undefined, inconclusive, uncertain, vague, misty, foggy, unclear; cryptic, Delphic, enigmatic(al), oracular, mysterious, puzzling; confusable:
The soothsayer's prophecies were sufficiently ambiguous to allow for several conflicting interpretations.
3 unreliable, undependable:
How can the doctor decide on a correct diagnosis when the symptoms are ambiguous?