Rather cheeky, which is not so hot (7)
I believe the answer is:
coolish
'hot' is the definition.
Both the answer and definition are adjectives.
Perhaps you can see a link between them that I don't see?
'rather cheeky which is not' is the wordplay.
I cannot really understand how this works, but
'is' is within the answer.
'not' could be 'o' (I've seen this in other clues) and 'o' is found within the answer.
This explanation may well be incorrect...
'so' acts as a link.
Can you help me to learn more?
(Another definition for coolish that I've seen is " Rather unfriendly".)