No explosive device used on eastern candidate (7)
I believe the answer is:
nominee
'candidate' is the definition.
(synonyms)
'no explosive device used on eastern' is the wordplay.
'explosive device' becomes 'mine' (mine is a kind of explosive device).
'used on' means one lot of letters go next to another.
'eastern' becomes 'e'.
'no'+'mine'+'e'='NOMINEE'
(Other definitions for nominee that I've seen before include "One put forward as a candidate" , "His/her name is put forward" , "Person standing for office" , "No real owner" , "One named as candidate" .)