Plain circled by lion perhaps for entertainment (7)
I believe the answer is:
cabaret
'for entertainment' is the definition.
(cabaret is a kind of entertainment)
'plain circled by lion' is the wordplay.
'plain' becomes 'bare' (similar in meaning).
'circled by' indicates putting letters inside (I've seen this in other clues).
'lion' becomes 'cat' (lions are big cats).
'bare' inserted into 'cat' is 'CABARET'.
'perhaps' acts as a link.
(Other definitions for cabaret that I've seen before include "Liza Minnelli's entertainment?" , "Floor show and name of great musical" , "Variety entertainment" , "Musical - nightclub entertainment" , "Floor-show as in nightclub" .)