VI'CIATE, v.t. [L. vitio. This veb is usually written vitiate; but as vice, from L. vitius, is established, it would be well to write the verb viciate, as we write appreciate and depreciate, from L. pretium.]

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.