Break in card game (4)
I believe the answer is:
snap
This clue is a double definition.
'break' is the first definition.
(I know that snap is a type of break)
'card game' is the second definition.
(simple card game)
'in' is the link.
(Other definitions for snap that I've seen before include "Still" , "Speak sharply or break suddenly" , "Lose cool" , "Break suddenly and cleanly" , "Card game for children" .)