Chum got very hot around end of afternoon (6)
I believe the answer is:
friend
'chum' is the definition.
(I've seen this in another clue)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for friend that I've seen before include "Pal, amigo" , "China" , "Person regarded with trust and affection" , "One who gives proof of genuine regard" , "Close associate" .)