blackball vs contradict

blackball is a noun but contradict is not a noun.

Word	Noun	Adjective	Verb	Adverb
blackball	Yes	No	Yes	No
contradict	No	No	Yes	No

As verbs, contradict is a hypernym of blackball; that is, contradict is a word with a broader meaning than blackball:

Other hypernyms of blackball include controvert, oppose.

blackball (noun)	contradict (noun)
the act of excluding someone by a negative vote or veto

blackball (verb)	contradict (verb)
expel from a community or group	prove negative; show to be false
vote against; refuse to endorse; refuse to assent	deny the truth of
	be resistant to
	be in contradiction with