veto vs defeat

veto and defeat both are nouns.

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

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

Other hyponyms of veto include kill, shoot down, vote down, vote out.

veto (noun)	defeat (noun)
a vote that blocks a decision	an unsuccessful ending to a struggle or contest
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)	the feeling that accompanies an experience of being thwarted in attaining your goals

veto (verb)	defeat (verb)
command against	win a victory over
vote against; refuse to endorse; refuse to assent	thwart the passage of