veto

an authoritative prohibition : interdiction

a power of one department or branch of a government to forbid or prohibit finally or provisionally the carrying out of projects attempted by another department; especially : a power vested in a chief executive to prevent permanently or temporarily the enactment of measures passed by a legislature

the exercise of such authority

to refuse to admit or approve : prohibit; also : to refuse assent to (a legislative bill) so as to prevent enactment or cause reconsideration

having enough potential votes to be enacted over a veto or to override vetoes consistently