Which term describes the act of canceling something permanently?

The act of canceling something permanently is best described by the term "revoke." To revoke means to officially cancel or withdraw a right, order, or agreement, making it no longer valid or in effect. This term is often used in legal and formal contexts, such as the revocation of a license or contract, where the intent is to render the original document or agreement void and unenforceable.

The other terms, while related to cancellation, do not carry the specific connotation of permanence that "revoke" does. For example, "nullify" means to render something legally void but may not imply a formal action to cancel. "Terminate" refers to bringing something to an end, but it doesn’t necessarily imply that the action is permanent. "Abrogate" involves formally repealing or doing away with a law, but it is often used in a more legislative context rather than general cancellation. Thus, the distinction in context and usage makes "revoke" the most accurate term to describe the act of canceling something permanently.