Theatrical male in beret (4)
I believe the answer is:
camp
'theatrical' is the definition.
(I've seen this before)
'male in beret' is the wordplay.
'male' becomes 'm' (common abbreviation).
'in' indicates putting letters inside.
'beret' becomes 'cap' (beret is a type of cap).
'm' placed within 'cap' is 'CAMP'.
(Other definitions for camp that I've seen before include "Set up tent - affected" , "holiday venue" , "Affected - group of tents" , "Temporary military site" , "Foppish" .)