Chance in card game initially blown (5)
I believe the answer is:
evens
'chance' is the definition.
(I've seen this before)
'card game initially blown' is the wordplay.
'card game' becomes 'sevens' (sevens is a kind of card game).
'initially blown' means to remove the first letter.
'sevens' with its first letter removed is 'EVENS'.
'in' acts as a link.
(Other definitions for evens that I've seen before include "Balanced odds" , "Exchange, substitute" , "Oddly, these could be odds" , "Chances" , "Smooths the odds" .)