Just a kind of entertainment (4)
I believe the answer is:
fair
I believe this clue is a triple definition!
'just' is the first definition.
('fair' is associated in meaning with 'just')
'a kind' is the second definition.
(I have seen 'kind of entertainment' mean 'fair' so perhaps 'kind' could also mean 'fair')
'of' acts as a link.
'entertainment' is the third definition.
(fair is a kind of entertainment)
(Other definitions for fair that I've seen before include "[OPPOSITE OF] Dark" , "Just - blonde - outdoor entertainment" , "Equitable or blond" , "square" , "Just - swings and roundabouts" .)