What is the president's constitutional power to reject acts of Congress called?

The power of the president to reject acts of Congress is referred to as a veto. This authority is outlined in Article I, Section 7 of the U.S. Constitution, granting the president the right to refuse to sign legislation passed by both houses of Congress. This mechanism serves as a check on legislative power, allowing the president to influence what laws come into effect. When a president vetoes a bill, Congress has the option to override that veto with a two-thirds majority vote in both the House of Representatives and the Senate, although such overrides are challenging to achieve.

The other terms listed do not pertain to the presidential veto. Cloture is a procedure used in the Senate to end a filibuster, which is a tactic employed to delay or prevent a vote on a bill. The whip system refers to party members responsible for ensuring party discipline and secure votes within their respective parties, but it does not relate to any presidential powers.