Disprove (5)
'disprove' is the definition.
(I know that rebut is a more specific form of the action disprove)
This is all the clue.
(Other definitions for rebut that I've seen before include "Tuber (anag.)" , "Overturn" , "Confute" , "Prove the claim wrong" , "Brute can refute" .)
'disprove' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for belie that I've seen before include "Fail to justify" , "Confute" , "Show to be untrue" , "Contradict" .)
'disprove' is the definition.
(I know that refute is a more specific form of the action disprove)
This is all the clue.
(Other definitions for refute that I've seen before include "Prove something to be wrong" , "Negate" , "Disprove" , "Prove that statement or accusation is wrong" , "Prove to be incorrect" .)
'disprove' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for repudiate that I've seen before include "Reject and refuse to acknowledge" , "Make a disclaimer" , "Reject as untrue or unjust" , "Reject or deny as unfounded" , "Deny the truth of (something)" .)