Ancient city, or a new one adopted by charity (7)
I believe the answer is:
antioch
'ancient city' is the definition.
(I've seen this before)
'a new one adopted by charity' is the wordplay.
'a new' becomes 'an' (I've seen this in other clues).
'one' becomes 'i' (Roman numeral).
'adopted by' is an insertion indicator (I've seen this in other clues).
'charity' becomes 'toch' (TocH is a Christian charity).
'i' going into 'toch' is 'tioch'.
'an'+'tioch'='ANTIOCH'
'or' acts as a link.
(Other definitions for antioch that I've seen before include "early Christian centre" , "Early centre of Christianity" , "Ancient name for Antakya in Turkey" , "Ancient Syrian city" , "Southern Turkish city" .)