What term refers to the rejection of a bill by the President?

The term that refers to the rejection of a bill by the President is "veto." A veto occurs when the President formally declines to approve a piece of legislation passed by Congress, effectively preventing it from becoming law. This power is an important aspect of the checks and balances inherent in the American political system, allowing the executive branch to check the legislative branch.

The veto can take multiple forms, such as a regular veto, where the President sends the bill back to Congress with a message explaining the rejection, or a pocket veto, which is a specific type of veto where the President does not sign the bill into law within a certain time frame and Congress adjourns, thus preventing its enactment without a formal rejection.

In contrast, a filibuster refers to a strategy employed in the Senate to delay or block legislative action, and a proclamation is a public announcement or declaration made by the President. Neither of these terms involves the active process of rejecting a bill like a veto does.