He scored heroin with Bianca occasionally (4)
I believe the answer is:
bach
'he scored' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'heroin with bianca occasionally' is the wordplay.
'heroin' becomes 'H' (H is a slang term for heroin).
'with' says to put letters next to each other.
'occasionally' means one should take alternating letters (letters taken at regular intervals or occasions).
The alternate letters of 'bianca' are 'bac'.
'h' put after 'bac' is 'BACH'.
Can you help me to learn more?
(Other definitions for bach that I've seen before include "German composer (affectionate to a Welshman?)" , "JS --, baroque composer" , "German organist and composer, d. 1750" , "Family of German composers" , "Goldberg Variations composer, d. 1750" .)