Prove to be incorrect (6)
I believe the answer is:
refute
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">prove to be incorrect</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for refute that I've seen before include "Rebut; deny" , "Contradict, prove that statement is wrong" , "Prove that statement or accusation is wrong" , "Negate" , "Prove something to be wrong" .)