Shorten a card game (7)
I believe the answer is:
'shorten' is the definition.
'a card game' is the wordplay.
'card game' becomes 'bridge' (bridge is a kind of card game).
(Other definitions for abridge that I've seen before include "(US) cattle-pen" , "Edit down" , "Make a precis of" , "Big read (anag) - shorten text" , "Abbreviate, contract" .)