veto
This term carries a heavy sense of absolute authority and unilateral power. It is not a simple disagreement or a request for revision, but a definitive stop that halts a process entirely. It evokes an image of a single hand slamming down on a table to end a discussion. While it originates in high-level government and constitutional law, it is frequently used in corporate or familial settings to describe a person who holds the final say. In these casual contexts, it suggests a power imbalance where one person can override the consensus of a group.
Countable when referring to a specific instance of rejection (he issued two vetoes). Uncountable when referring to the general legal authority (the power of veto).
Meanings
A constitutional right to reject a decision or proposal made by a law-making body.
"The president decided to exercise his veto on the new healthcare bill."