City with zero money deserted by one banking on thrift (7)
I believe the answer is:
economy
'thrift' is the definition.
(I know that economy is a type of thrift)
'city with zero money deserted by one banking on' is the wordplay.
'city' becomes 'EC' (postcode for the City of London).
'with' says to put letters next to each other.
'zero' becomes 'O' (O resembles 0).
'deserted by' suggests deleting specific letters.
'banking' means one lot of letters goes inside another.
'money' with 'one' taken out is 'my'.
'ec'+'o'+'my'='ecomy'
'ecomy' enclosing 'on' is 'ECONOMY'.
(Other definitions for economy that I've seen before include "Me coy? No! (anag)" , "Thrift - national production, distribution and consumption" , "A country's system of production, distribution and consumption" , "Financial prudence" , "See 22" .)