Opportunist appearing in court, shortly (7)
I believe the answer is:
chancer
'opportunist' is the definition.
(someone taking chances)
'court shortly' is the wordplay.
'court' becomes 'chancery' (type of court).
'shortly' means to remove the last letter.
'chancery' with its last letter taken off is 'CHANCER'.
'appearing in' acts as a link.
(Other definitions for chancer that I've seen before include "Exploiter of opportunity" , "Unscrupulous opportunist" , "Unscrupulous sort" , "opportunistic sort" , "One taking risks" .)