Singer in pub getting one note wrong (8)
I believe the answer is:
baritone
'singer' is the definition.
(I know that baritone is a type of singer)
'pub getting one note wrong' is the wordplay.
'pub' becomes 'bar' (both are drinking establishments).
'getting' indicates putting letters inside.
'one' becomes 'i' (Roman numeral).
'wrong' indicates an anagram.
'note' anagrammed gives 'tone'.
'i' placed inside 'tone' is 'itone'.
'bar'+'itone'='BARITONE'
'in' is the link.
(Other definitions for baritone that I've seen before include "Male voice with deep register" , "Male voice between bass and tenor" , "Male singer between tenor and bass" , "Male singer in boater, strangely" , "Adult male singing voice" .)