Composer in pub having drink half-heartedly (6)
I believe the answer is:
barber
'composer' is the definition.
(Samuel Barber)
'in pub having drink half-heartedly' is the wordplay.
'in' indicates putting letters inside.
'pub' becomes 'bar' (I've seen this before).
'having drink' becomes 'rb' (I am not sure about this - if you are sure you should believe this answer much more).
'half' means to take half the letters.
'heartedly' becomes 'ed' (I've seen this in other clues).
'ed' with half the letters taken is 'e'.
'rb'+'e'='rbe'
'bar' enclosing 'rbe' is 'BARBER'.
Can you help me to learn more?
(Other definitions for barber that I've seen before include "Men's haircutter, musically of Seville?" , "producing various versions of Hair?" , "Hairdresser for men - musically from Seville" , "Sweeney Todd's profession in Fleet Street" , "Hair stylist" .)