Follower of a neat herd (8)
I believe the answer is:
adherent
'follower' is the definition.
(I know that adherent is a type of follower)
'of a neat herd' is the wordplay.
'of' indicates an anagram (the answer comes from or 'of' the letters).
'neat'+'herd'='neatherd'
'neatherd' is an anagram of 'ADHERENT'.
(Other definitions for adherent that I've seen before include "One supports" , "lover" , "Person supporting" , "Loyal follower, one who sticks" , "sticker" .)