Equality over top of nude model (7)
I believe the answer is:
paragon
'model' is the definition.
(a paragon is a model example of something)
'equality over top of nude' is the wordplay.
'equality' becomes 'par' (synonyms).
'over' becomes 'ago' (both can mean in the past).
'top of' says to take the initial letters.
The initial letter of 'nude' is 'n'.
'par'+'ago'+'n'='PARAGON'
(Other definitions for paragon that I've seen before include "Role model" , "Perfect type" , "Model of conduct" , "A perfect person - pagan or what?" , "Perfect diamond" .)