Brilliant, a foreign court no longer in existence (7)
I believe the answer is:
defunct
'brilliant a foreign court no longer in existence' is the definition.
I can't tell whether this defines the answer.
'brilliant a foreign court' is the wordplay.
'brilliant' becomes 'def' (def can informally mean excellent).
'a foreign' becomes 'un' ('a' translated into French).
'court' becomes 'ct' (abbreviation used in road names).
'def'+'un'+'ct'='DEFUNCT'
Can you help me to learn more?
(Other definitions for defunct that I've seen before include "Extinct" , "No longer alive" , "No longer in use" , "No longer operative" , "Dead, no longer existing" .)