Crowd supports occasionally sick game (8)
I believe the answer is:
scrabble
'game' is the definition.
(Scrabble is an example)
'crowd supports occasionally sick' is the wordplay.
'crowd' becomes 'rabble' (rabble is a kind of crowd**).
'supports' is a charade indicator (letters next to each other) (bottom letters provide a support for the top ones).
'occasionally' indicates alternate letters.
The alternating letters of 'sick' are 'sc'.
'rabble' after 'sc' is 'SCRABBLE'.
(Other definitions for scrabble that I've seen before include "Word-building game" , "Hypothetical, imaginary" , "Popular word game played on a board" , "Popular word game using board" , "Very popular word-board gane" .)