Thrift in company trapped by money supply (7)
I believe the answer is:
economy
'thrift' is the definition.
(I've seen this before)
'company trapped by money supply' is the wordplay.
'company' becomes 'co' (abbreviation).
'trapped by' means one lot of letters goes inside another.
'supply' indicates an anagram (in a supple way).
'money' with letters rearranged gives 'enomy'.
'co' put inside 'enomy' is 'ECONOMY'.
'in' acts as a link.
(Other definitions for economy that I've seen before include "Using little" , "Me coy? No! (anag)" , "Thrift - national production, distribution and consumption" , "Careful expenditure" , "Financial saving" .)