Note smoker in pub is a musician (8)
I believe the answer is:
bagpiper
'musician' is the definition.
(bagpiper is a kind of musician)
'note smoker in pub' is the wordplay.
'note' becomes 'g' (musical note**).
'smoker' becomes 'pipe'.
'in' means one lot of letters goes inside another.
'pub' becomes 'bar' (I've seen this before).
'g'+'pipe'='gpipe'
'gpipe' inserted inside 'bar' is 'BAGPIPER'.
'is a' acts as a link.
(Other definitions for bagpiper that I've seen before include "(Scottish) musician" , "Scots musician" , "Pibroch player" , "Wind musician" , "One blows out air" .)