Describing someone who keeps their sexual orientation or gender identity secret. He remained closeted for many years, fearing the reaction of his family and friends.
Describing someone who keeps a particular belief, interest, or aspect of their identity hidden from others. She was a closeted fan of science fiction, only discussing it with her closest friends.
Secluded or confined in a private room, especially for consultation or deliberation. The negotiators remained closeted in the conference room for hours.