Concealed too much in court (6)
I believe the answer is:
covert
'concealed' is the definition.
(associated in meaning)
'too much in court' is the wordplay.
'too much' becomes 'over' (I've seen this before).
'in' indicates putting letters inside.
'court' becomes 'ct'.
'over' placed inside 'ct' is 'COVERT'.
(Other definitions for covert that I've seen before include "Area of undergrowth in which animals hide" , "place for game" , "Concealed, secret" , "Hidden - thicket" , "A fox's retreat, secret" .)