Unpaid companion in a biblical city (7)
I believe the answer is:
amateur
'unpaid' is the definition.
(similar in meaning)
'companion in a biblical city' is the wordplay.
'companion' becomes 'mate' (both can mean a friend).
'in' means one lot of letters goes inside another.
'biblical city' becomes 'Ur' (city in the Hebrew bible).
'a'+'ur'='aur'
'mate' going inside 'aur' is 'AMATEUR'.
(Other definitions for amateur that I've seen before include "Inept, non-professional" , "Athlete who performs without payment" , "lacking professional expertise" , "I'm no expert!" , "One who pursues an activity as a pastime only" .)