Willing behind eccentric bridge, say (4,4)
I believe the answer is:
card game
'bridge say' is the definition.
(I know that contract bridge is a type of trick-taking game)
'willing behind eccentric' is the wordplay.
'willing' becomes 'game' (game can mean willing to do something).
'behind' means one lot of letters go next to another.
'eccentric' becomes 'card' (card can mean an eccentric person).
'game' put after 'card' is 'CARD GAME'.
(Other definitions for card game that I've seen before include "'Rummy or bridge, say (4,4)'" , "Patience for one" , "solo, perhaps" , "nap perhaps" , "Poker or whist, say" .)