Indoor sport crowd (6)
I believe the answer is:
squash
I believe this clue is a double definition.
'indoor sport' is the first definition.
(I know that squash is a type of indoor sport)
'crowd' is the second definition.
(thesaurus)
(Other definitions for squash that I've seen before include "Vegetable on court?" , "In which one serves" , "Suppress - game" , "Fruit - drink - crush" , "Game; crush, squeeze" .)