Portray nude on a grand scale (4)
I believe the answer is:
epic
'on a grand scale' is the definition.
(I've seen this before)
'portray nude' is the wordplay.
'portray' becomes 'depict' (synonyms).
'nude' says to take the centre (the word is stripped of its outer letters).
The middle of 'depict' is 'EPIC'.
(Other definitions for epic that I've seen before include "On a grand scale like long poem" , "eg Beowulf" , "Heroic narrative verse" , "Long poem telling of great events" , "Long poem set in nice picture" .)