Bear and cat involved in entertainment (7)
I believe the answer is:
cabaret
'entertainment' is the definition.
(I've seen this before)
'bear and cat involved' is the wordplay.
'and' says to put letters next to each other (I've seen this in other clues).
'involved' indicates anagramming the letters (involved can mean confusing or complex).
'bear' put after 'cat' is 'catbear'.
'catbear' is an anagram of 'CABARET'.
'in' is the 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" .)