Denied (8)
'denied' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for negated that I've seen before include "Abrogated" , "Made ineffective" , "Denied" , "Nullified" , "Cancelled or destroyed the effect of something" .)
'denied' is the definition.
('refuse' can be a synonym of 'deny')
This is the entire clue.
(Other definitions for refused that I've seen before include "Not accepted" , "Was unwilling to accept" , "turned down appeal" , "Said no (7)" , "Declined, rejected" .)
'denied' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for refuted that I've seen before include "Denied" , "Negated" , "Prove to be false or incorrect" , "Proved false" , "Proved (a statement) to be wrong" .)
'denied' is the definition.
(to gainsay is to deny or dispute something)
This is all the clue.
(Other definitions for gainsaid that I've seen before include "Formally denied or contradicted" , "Challenged" .)