Closeted
Etymology
Nondisclosure of one's sexual orientation or gender identity preceded the use of "closet" as a term for the act. For example, the writer Thomas Mann entered a heterosexual marriage with a woman in 1905, and had six children, but discussed his attraction to men in his private diary, which by contemporary terms would have designated him a closeted homosexual man.
Etymology
D. Travers Scott claims that the phrase "coming out of the closet", along with its derivative meanings of "coming out" and "closeted", has its origins in two different metaphors. "Coming out" was first a phrase used in the early 20th century in reference to a young woman attending a debutante ball, such that she was "coming out" into society. In past times, the word "closet" meant "bedroom", so one's sexuality was not shown beyond there. Later in the 1960s, the metaphor of a "skeleton in the closet", which meant to hide a secret due to taboos or social stigmas, was also used in reference to a gender identity or sexuality that one may not wish to disclose. As such, to reveal one's LGBTQ+ identity that was previously hidden or kept secret was to allow a skeleton to come out of the closet.
Etymology
One linguistic study suggests that the transgender community may use different vocabulary to refer to the disclosure status of one's gender identity, such as "stealth)" in place of "closeted".