Boy's from Pisa, actually (5)
I believe the answer is:
isaac
'boy's' is the definition.
'from pisa actually' is the wordplay.
'from' indicates the answer is hidden within the clue.
'ISAAC' is hidden in the letters of 'pisa actually'.
(Other definitions for isaac that I've seen before include "Jewish name?" , "Sarah's son" , "Abraham's son" , "Singer" , "According to the book, twins' dad" .)