Wicked man undermining pub, West Indian (9)
I believe the answer is:
barbadian
'west indian' is the definition.
(I know that Barbadian is a type of west indian)
'wicked man undermining pub' is the wordplay.
'wicked' becomes 'bad' (similar in meaning).
'man' becomes 'ian' (man's name).
'undermining' says to put letters next to each other.
'pub' becomes 'bar' (both are drinking establishments).
'bad'+'ian'='badian'
'badian' put after 'bar' is 'BARBADIAN'.
(Other definitions for barbadian that I've seen before include "one from West Indies" , "West Indian" , "from a Caribbean island" .)