Cheeky jester clad in old cape one's invited to court (6,7)
I believe the answer is:
expert witness
'one's invited to court' is the definition.
I can't judge whether this definition defines the answer.
'cheeky jester clad in old cape' is the wordplay.
'cheeky' becomes 'pert' (pert can mean cheeky or insolent).
'jester' becomes 'wit' (both can mean a comical person).
'clad in' means one lot of letters goes inside another.
'old' becomes 'ex' (prefix meaning former or onetime).
'cape' becomes 'ness' (synonyms).
'pert'+'wit'='pertwit'
'ex'+'ness'='exness'
'pertwit' inserted into 'exness' is 'EXPERT WITNESS'.
Can you help me to learn more?
(Other definitions for expert witness that I've seen before include "One providing specialist testimony" , "Wiser next step? (anag)" , "Court specialist" .)