Need Juliet in support for game (9)
I believe the answer is:
blackjack
'game' is the definition.
(blackjack is a card game)
'need juliet in support' is the wordplay.
'need' becomes 'lack' (to lack something is to be in need of it).
'juliet' becomes 'J' (phonetic alphabet: alpha, bravo, charlie etc.).
'in' means one lot of letters goes inside another.
'support' becomes 'back' (synonyms).
'lack'+'j'='lackj'
'lackj' going within 'back' is 'BLACKJACK'.
'for' is the link.
(Other definitions for blackjack that I've seen before include "2 8 [CASINO GAME]" , "Vingt-et-un - pirates' ensign" , "Gambling card game" , "Club" , "Casino card game" .)