The utter acme of resentment (5)
I believe the answer is:
pique
'resentment' is the definition.
(I've seen this before)
'the utter acme' is the wordplay.
'the utter' shows a homophone (sound like) (I've seen 'uttered' mean this).
'acme' becomes 'peak' (synonyms).
'peak' sounds like 'PIQUE'.
'of' is the link.
(Other definitions for pique that I've seen before include "Provoke" , "Nettle" , "Hurt feelings" , "Resentment at a slight" , "Feeling of wounded pride" .)