Villain's accent, not British (5)
I believe the answer is:
rogue
'villain's' is the definition.
(rogue is a kind of villain)
'accent not british' is the wordplay.
'accent' becomes 'brogue' (brogue can mean a Scottish or Irish accent).
'not' indicates named letters should be taken away.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'brogue' with 'b' removed is 'ROGUE'.
(Other definitions for rogue that I've seen before include "Diverging from type" , "Stray" , "Miscreant" , "Deceitful and unreliable scoundrel" , "Mischievous person" .)