The girl in the pool (5)
I believe the answer is:
kitty
I believe this clue is a double definition.
'the girl' is the first definition.
'the pool' is the second definition.
(both can mean a shared fund)
'in' acts as a link.
(Other definitions for kitty that I've seen before include "Perhaps a small Abyssinian" , "Pot of money" , "Girl's name -- pooled money" , "Pool - puss" , "One part of litter queen dropped" .)