Former partner with cheeky humour quashing point one's employed in court (6,7)
I believe the answer is:
expert witness
'humour quashing point one's employed in court' is the definition.
I can't judge whether this defines the answer.
'former partner with cheeky' is the wordplay.
'former' becomes 'ex' (prefix meaning former or onetime).
'partner' becomes 'witness' (I am not sure about this - if you are sure you should believe this answer much more).
'with' says to put letters next to each other.
'cheeky' becomes 'pert' (pert can mean cheeky or insolent).
'witness' put after 'pert' is 'pertwitness'.
'ex'+'pertwitness'='EXPERT WITNESS'
Can you help me to learn more?
(Other definitions for expert witness that I've seen before include "Wiser next step? (anag)" , "Court specialist" , "One providing specialist testimony" .)