Candidate I’m backing - nobody English will accept that (7)
I believe the answer is:
nominee
'candidate i'm backing nobody english will accept that' is the definition.
'nominee' can be an answer for 'candidate' (synonyms). I am not certain of the rest of the definition.
'nobody english will accept that' is the wordplay.
'nobody' becomes 'none' (not a single person).
'english' becomes 'E' (abbreviation).
'will accept' is an insertion indicator.
'that' becomes 'mi' (I can't justify this - if you can you should believe this answer much more).
'none'+'e'='nonee'
'nonee' enclosing 'mi' is 'NOMINEE'.
Can you help me to learn more?
(Other definitions for nominee that I've seen before include "His/her name is put forward" , "He's put forward" , "Chosen person" , "One proposed for election" , "Person put up for a post" .)