Made ineffective (9)
'made ineffective' is the definition.
('nullify' can be a synonym of 'make ineffective')
This is the entire clue.
(Other definitions for nullified that I've seen before include "Scrubbed" , "revoked" , "Abrogated" , "Made invalid" , "Cancelled out" .)
'made ineffective' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for negated that I've seen before include "Nullified" , "Made ineffective" , "Cancelled or destroyed the effect of something" , "Discredited" , "Abrogated" .)