Burlesque model holds back at the end (4)
I believe the answer is:
skit
'burlesque' is the definition.
(I've seen this before)
'model holds back at the end' is the wordplay.
'model' becomes 'sit' ('sit' can be a synonym of 'model'**).
'holds' means one lot of letters goes inside another.
'at the end' says to take the final letters.
The last letter of 'back' is 'k'.
'sit' going around 'k' is 'SKIT'.
(Other definitions for skit that I've seen before include "satirical observation" , "Short comic piece" , "A piece of humorous mimicry" , "Satirical drama" , "Comic routine" .)