Old money court makes obsolete (7)
I believe the answer is:
extinct
'obsolete' is the definition.
(I've seen this before)
'old money court' is the wordplay.
'old' becomes 'ex' (prefix meaning former or onetime).
'money' becomes 'tin' (old-fashioned slang term for money).
'court' becomes 'ct' (abbreviation used in road names).
'ex'+'tin'+'ct'='EXTINCT'
'makes' is the link.
(Other definitions for extinct that I've seen before include "No longer in existence" , "Long gone, like te dinosaur" , "No longer around" , "Wiped out" , "gone for ever" .)