treacherous

Guilty of or characterized by betrayal of confidence or trust; perfidious.

Characterized by unforeseen or hidden hazards; dangerous or deceptive.

Using treachery; violating allegiance or faith pledged; traitorous to the state or sovereign; perfidious in private life; betraying a trust.

Marked by deceitfulness or perfidy; characteristic of a traitor.

Having a good, fair, or sound appearance, but worthless or bad in character or quality; deceptive; not to be depended on or trusted.