Rebut means to refute by argument or evidence, to contradict.
Rebut is a verb.
Synonyms: answer, challenge, invalidate, refute, deny, disprove, confute, counter.
Antonyms: confirm, support, vindictive, prove, corroborate, substantiate.
No one tried to rebut Mr. Ravi's argument; they knew he would punch the first person who tired to contradict him.
Everyone thought Rani was insane, but no one could rebut her argument.