Secret meeting (8)
I believe the answer is:
conclave
'secret meeting' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for conclave that I've seen before include "Group meeting (to choose a pope?)" , "Papal election meeting" , "Private meeting (to elect a pope?)" , "An assembly of cardinals to elect pope" , "Confidential or secret meeting" .)