Disproved (7)
I believe the answer is:
refuted
'disproved' is the definition.
('refute' can be a synonym of 'disprove')
This is the entire clue.
(Other definitions for refuted that I've seen before include "Proved (a statement) to be wrong" , "Negated" , "Denied" , "Disproved" , "Proved false" .)