Unfriendly, but not really heated (4)
I believe the answer is:
cool
'unfriendly' is the definition.
(associated in meaning)
'not really heated' is the wordplay.
I cannot quite understand how this works, but
'not' could be 'o' (I've seen this in other clues) and 'o' is located in the answer.
The remaining letters 'col' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'but' acts as a link.
Can you help me to learn more?
(Other definitions for cool that I've seen before include "Casual and confident - not heated" , "Calm; chilly" , "At fairly low temperature" , "Calm; not warm" , "Unemotional; excellent" .)