Queen leaving court is risky (6)
I believe the answer is:
chancy
'risky' is the definition.
(synonyms)
'queen leaving court' is the wordplay.
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'leaving' indicates named letters should be taken away.
'court' becomes 'chancery' (type of court).
'chancery' with 'er' taken away is 'CHANCY'.
'is' acts as a link.
(Other definitions for chancy that I've seen before include "Informally uncertain or risky" , "'Dodgy, dicey (6)'" .)