Bear and cat involved in entertainment (7)
I believe the answer is:
cabaret
'entertainment' is the definition.
(cabaret is a kind of entertainment)
'bear and cat involved' is the wordplay.
'and' means one lot of letters go next to another.
'involved' is an anagram indicator (involved can mean confusing or complex).
'bear' put after 'cat' is 'catbear'.
'catbear' with letters rearranged gives 'CABARET'.
'in' acts as a link.
(Other definitions for cabaret that I've seen before include "Entertainment provided in a nightclub" , "Nightclub 12ac" , "Evening entertainment as in nightclub" , "goes on in nightclub?" , "Series of acts" .)