An American theatre award given to male opposite (7)
I believe the answer is:
antonym
'opposite' is the definition.
('antonym' can be a synonym of 'opposite')
'an american theatre award given to male' is the wordplay.
'an american theatre award' becomes 'antony' (I've seen this in other clues).
'given to' means one lot of letters go next to another.
'male' becomes 'm' (common abbreviation).
'antony'+'m'='ANTONYM'
(Other definitions for antonym that I've seen before include "Word that means the opposite of another" , "something completely different" , "opposing term" , "For villain, hero is one" , "As 'happy' is to 'sad' or 'long' to 'short'" .)