Combine having some fun, it entertains (5)
I believe the answer is:
unite
'combine' is the definition.
('unite' can be a synonym of 'combine')
'some fun it entertains' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'UNITE' is hidden within 'fun it entertains'.
'having' acts as a link.
(Other definitions for unite that I've seen before include "Join forces" , "Come, or join together" , "fuse" , "Amalgamate" , "Come together as allies or comrades" .)