"Annul a law" is a phrase commonly used in legal contexts to denote the act of revoking or invalidating a law. However, there are several other phrases that can be used synonymously with "annul a law." These include phrases such as "revoke a law," "nullify a law," "invalidate a law," "cancel a law," "rescind a law," and "void a law." All of these phrases express similar ideas of negating or undoing the effects of a particular law. In essence, they all refer to the act of rendering a law null and void, and therefore no longer legally enforceable.