Member of City guild — a disagreeable chap? (9)
I believe the answer is:
liveryman
'member of city guild' is the definition.
(as in a member of a livery company)
'a disagreeable chap?' is the wordplay.
'a disagreeable' becomes 'livery' (livery can mean disagreeable or easily annoyed).
'chap?' becomes 'man' (chap can mean a man).
'livery'+'man'='LIVERYMAN'
(Other definitions for liveryman that I've seen before include "One looking after hacks" , "Uniformed servant" , "Member of guild" , "Member of a City Company" .)