Long to be presented in court — the prestige! (6)
I believe the answer is:
cachet
'the prestige' is the definition.
('cachet' can be a synonym of 'prestige')
'long to be presented in court' is the wordplay.
'long' becomes 'ache' ('ache' can be a synonym of 'long').
'to be presented in' means one lot of letters goes inside another.
'court' becomes 'ct'.
'ache' placed within 'ct' is 'CACHET'.
(Other definitions for cachet that I've seen before include "(Mark of) distinction" , "Distinguishing mark or seal" , "Kudos" , "Prestige - seal of approval" , "Official seal - prestige" .)