The fellow holds a note for the builder (5)
I believe the answer is:
mason
'the builder' is the definition.
(I've seen this before)
'the fellow holds a note' is the wordplay.
'the fellow' becomes 'man' (fellow can mean a man).
'holds' means one lot of letters goes inside another.
'a note' becomes 'so' (musical note).
'man' going around 'so' is 'MASON'.
'for' is the link.
(Other definitions for mason that I've seen before include "One works with stone or brick" , "US comedian" , "Craftsperson who works with stone or brick" , "one wearing an apron" , "Builder in stone" .)