Resenting competing alongside extremists in election (7)
I believe the answer is:
envying
'resenting' is the definition.
(to resent is to feel envious or bitter)
'competing alongside extremists in election' is the wordplay.
'competing' becomes 'vying' ('vie' can be a synonym of 'compete').
'alongside' says to put letters next to each other.
'extremists in' says to hollow out the word (remove centre letters).
'election' with its centre taken out is 'en'.
'vying' after 'en' is 'ENVYING'.
(Other definitions for envying that I've seen before include "to find green?" , "Coveting" .)