disallow vs veto

disallow is not a noun while veto is a noun.

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

As verbs, disallow and veto are synonyms defined as:

Other synonyms of disallow include forbid, interdict, nix, prohibit, proscribe.

disallow (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)

disallow (verb)	veto (verb)
command against	command against
	vote against; refuse to endorse; refuse to assent