Secret Meeting, Clandestine Meeting
noun, verbal noun
A secrecy meet is a secret meeting. You know the password?
みっかい
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own. Note that みつ changes to みっ.
私達は密会によくこの部屋を利用しています。
We often make use of this room for secret meetings.