What is a nullify?

to render or declare legally void or inoperative: to nullify a contract.

Assuming you are the testator, you would execute a subsequent will nullifying any prior will.Added: If you are challenging the will, you would have to raise the issue of the testator's mental...

To nullify means to render ineffective. If you nullify a contract. a warranty, or even a marriage, the effect is as if the thing had never happened. In law ( which is sometimes redundant ) things are...

The Supreme Court can nullify an Act of Congress. They would have to say that it specifically contridicted the Constitution. The President could affect a law by refusing to enforce it.

void, invalidate, cancel, counteract