Resentment in summit discussed (5)
I believe the answer is:
pique
'resentment' is the definition.
(thesaurus)
'summit discussed' is the wordplay.
'summit' becomes 'peak' ('peak' can be a synonym of 'summit').
'discussed' shows a homophone (sound like).
'peak' is a homophone of 'PIQUE'.
'in' acts as a link.
(Other definitions for pique that I've seen before include "Umbrage; irritation" , "Petulant anger" , "Stimulate (one's curiosity)" , "Animosity" , "Equip (anag.)" .)