Boy of six immersed in pop (5)
I believe the answer is:
david
'boy' is the definition.
'six immersed in pop' is the wordplay.
'six' becomes 'VI' (Roman numerals).
'immersed in' means one lot of letters goes inside another.
'pop' becomes 'dad' (both can mean one's father).
'vi' placed within 'dad' is 'DAVID'.
'of' acts as a link.
(Other definitions for david that I've seen before include "- Copperfield (Dickens)" , "singer/harpist?" , "friend of Jonathan's?" , "Michelangelo statue" , "Welsh saint - French painter" .)