Game requiring a lot of water (4)
I believe the answer is:
pool
'game' is the definition.
(pool is a kind of game)
'a lot of water' is the wordplay.
I cannot really see how this works, but
'of' could be 'o' and 'o' is found within the answer.
'water' could be 'po' (Po is an example) and 'po' is found within the answer.
A single letter 'l' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
'requiring' acts as a link.
Can you help me to learn more?
(Other definitions for pool that I've seen before include "found in watery location" , "Accumulate" , "American game like snooker" , "Pond; table game" , "Ball game - small body of water" .)