Bubbly‘s cold, getting cooler (7)
I believe the answer is:
chipper
'bubbly's' is the definition.
(thesaurus)
'cold getting cooler' is the wordplay.
I cannot quite understand how this works, but
'cold' could be 'c' (eg on taps) and 'c' is present in the answer.
The remaining letters 'hipper' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for chipper that I've seen before include "Happy" , "employee in fast-food joint" , "Debonair" , "person damaging crockery?" , "golfer, perhaps?" .)