High-risk entertaining the queen's court (8)
I believe the answer is:
chancery
'court' is the definition.
(type of court)
'high-risk entertaining the queen's' is the wordplay.
'high-risk' becomes 'chancy' (chancy can mean risky).
'entertaining' means one lot of letters goes inside another.
'the queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'chancy' going around 'er' is 'CHANCERY'.
(Other definitions for chancery that I've seen before include "Division of the British Court of Justice" , "Division of the courts of justice" , "in which a wrestler may be held" , "Public record office" , "Embassy/consulate office" .)