Warmth of fire behind chain of mountains tops (10)
I believe the answer is:
compassion
'warmth' is the definition.
(thesaurus)
'fire behind chain of mountains tops' is the wordplay.
'fire' becomes 'passion' (I've seen this before**).
'behind' is a charade indicator (letters next to each other).
'tops' indicates taking the first letters.
The initial letters of 'chain of mountains' is 'com'.
'passion' after 'com' is 'COMPASSION'.
'of' acts as a link.
(Other definitions for compassion that I've seen before include "Sympathy for another's suffering" , "Fellow-feeling" , "Kindness" .)