Brief them to get answer from criminal leader in court case playing to the gallery (10)
I believe the answer is:
theatrical
'court case playing to the gallery' is the definition.
I can't judge whether this definition defines the answer.
'brief them to get answer from criminal leader in' is the wordplay.
'brief' means to remove the last letter.
'to get answer' becomes 'atrial' (I can't explain this - if you can you should give a lot more credence to this answer).
'from' means one lot of letters go next to another.
'leader' says to take the initial letters.
'in' indicates putting letters inside.
The first letter of 'criminal' is 'c'.
'them' with its last letter taken off is 'the'.
'the'+'atrial'='theatrial'
'theatrial' enclosing 'c' is 'THEATRICAL'.
Can you help me to learn more?
(Other definitions for theatrical that I've seen before include "overdramatic" , "Stagy" , "Relating to acting/actors" , "affected" , "Showbiz" .)