Drink over money one lost in card game (5)
I believe the answer is:
rummy
'card game' is the definition.
(rummy is a kind of card game)
'drink over money one lost' is the wordplay.
'drink' becomes 'rum' (I've seen this before**).
'over' says to put letters next to each other.
'lost' is a deletion indicator.
'money' with 'one' removed is 'my'.
'rum'+'my'='RUMMY'
'in' acts as a link.
(Other definitions for rummy that I've seen before include "game of cards" , "Card game; strange; like a spirit" , "Set, sequence card game" , "Gin perhaps?" , "Two-pack card game" .)