Somewhat heated, months after serious conflict (4)
I believe the answer is:
warm
'somewhat heated' is the definition.
(warm but not too hot)
'months after serious conflict' is the wordplay.
'months' becomes 'm'.
'after' says to put letters next to each other.
'serious conflict' becomes 'war' (military conflict).
'm' put after 'war' is 'WARM'.
(Other definitions for warm that I've seen before include "easily aroused" , "showing enthusiasm" , "Affectionate - balmy" , "Pleasantly hot" , "On the brink of making discovery" .)