Villain is after British accent (6)
I believe the answer is:
brogue
'accent' is the definition.
(I've seen this before)
'villain is after british' is the wordplay.
'villain' becomes 'rogue' (rogue is a kind of villain).
'is after' says to put letters next to each other.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'rogue' put after 'b' is 'BROGUE'.
(Other definitions for brogue that I've seen before include "Style of shoe - style of accent" , "Stout shoe - Irish accent" , "Marked accent" , "Lilting Irish accent" , "Patterned shoe, accent" .)