Just cause, providing venue for outdoor entertainment (10)
I believe the answer is:
fairground
'venue for outdoor entertainment' is the definition.
'just cause' is the wordplay.
'just' becomes 'fair' ('fair' is associated in meaning with 'just').
'cause' becomes 'ground' (**).
'fair'+'ground'='FAIRGROUND'
'providing' is the link.
(Other definitions for fairground that I've seen before include "good enough for entertainment" , "Scary ride here perhaps" , "Entertainment venue" , "Where one plays" , "Entertainment centre" .)