1. to injure the substance or properties of a thing so as to impair its value, and lessen or destroy its use; to make less pure, or wholly impure; to deprave, in a physical or moral sense; as, to viciate the blood; to viciate taste or style; to viciate morals.
2. To render defective and thus destroy the validity of; to invalidate by defect; as, to viciate a deed or bond.