Cooler setter essentially renounced drink (5)
I believe the answer is:
icier
'cooler' is the definition.
Both the definition and answer are comparative adjectives. Perhaps there's a link between them I don't understand?
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for icier that I've seen before include "More cold - really freezing" , "More cold or frozen" , "much less friendly" , "More glacial" , "with more reserve" .)