controvert vs veto

controvert is not a noun while veto is a noun.

Word	Noun	Adjective	Verb	Adverb
controvert	No	No	Yes	No
veto	Yes	No	Yes	No

As verbs, veto is a hyponym of controvert; that is, veto is a word with a more specific, narrower meaning than controvert:

Other hyponyms of controvert include blackball, negative, dissent, protest, resist.

controvert (noun)	veto (noun)
	a vote that blocks a decision
	the power or right to prohibit or reject a proposed or intended act (especially the power of a chief executive to reject a bill passed by the legislature)

controvert (verb)	veto (verb)
prove to be false or incorrect	command against
be resistant to	vote against; refuse to endorse; refuse to assent