Closeted

Closeted and in the closet are metaphors for lesbian, gay, bisexual, transgender, LGBTQ+ people who have not disclosed their sexual orientation or gender identity and aspects thereof, including sexual identity and sexual behavior. It can also be used to describe anyone who is hiding part of their identity because of social pressure.
Background.
In late 20th-century America, the closet had become a central metaphor for grasping the history and social dynamics of gay life, along with the concept of coming out. The closet narrative sets up an implicit dualism between being "in" or being "out". Those who are "in" are often stigmatized as living false, unhappy lives. However, though many people would prefer to be "out" of the closet, there are numerous social, economic, familial, and personal repercussions that lead to them remaining, whether consciously or unconsciously, "in" the closet. For example, the Lavender Scare, which implemented Executive Order #10450 and banned all gay and lesbians from working in the U.S federal government, forced employees who wished to retain their jobs to remain in the closet. Sometimes people have remained in the closet because they themselves have had difficulty understanding or accepting their sexuality. The decision to come out or remain in the closet is considered a deeply personal one, and outing remains controversial in today's culture.
In the 21st century, the related concept of a "glass closet" emerged in LGBT discourse. This term describes public figures, such as entertainers or politicians, who are out of the closet in their personal lives and do not engage in the tactics (such as entering a lavender marriage or publicly dating a person of the opposite sex as a "beard") that were historically used by closeted celebrities to disguise their sexual identity, but have not formally disclosed their sexual orientation on the public record — and who, thus, are technically neither fully in the closet nor fully out of it. Some celebrities that were forced to be in the closet are Colton Haynes and Ricky Martin. Lavender marriages occurred throughout Hollywood in order to advance and maintain ones career and have been happening since the early 20th century. Closeting is not only seen in celebrities, but also in the media that is produced. Popular television shows utilize metaphors to show closeting, and these metaphors differ based on how it relates to society at the time.
Effects.
In the early stages of the lesbian, gay or bisexual identity development process, people often feel confused and experience turmoil. In 1993, Michelangelo Signorile wrote "Queer in America", in which he explored the harm caused both to a closeted person and to society in general by being closeted.
Seidman, Meeks, and Traschen (1999) argue that "the closet" may be becoming an antiquated metaphor in the lives of modern-day Americans for two reasons.
The closet, however, is difficult for any non-heterosexual, non-cisgender identified person to fully come "out" of, whether or not that person desires to do so. Scholar Eve Kosofsky Sedgwick, author of the "Epistemology of the Closet", discusses the difficulty with the closet: 
Recent attention to bullying of LGBTQ youth and teens in the United States gives an indication that many youth and teens remain closeted throughout their educational years and beyond for fear of disapproval from parents, friends, teachers, and community members. To remain in the closet offers an individual a layer of protection against ridicule and bullying ; however, to remain in the closet typically takes a toll on the mental health of the individual, especially in the adolescent years as reflected in suicide rates among LGBTQ youths. Being closeted can also have different effects on the mental health on men and women. In a study done by John E. Pachankis from Yale University and Susan D. Cochran and Vickie M. Mays from the University of California, it was found that women who were closeted were twice as likely to report depressive episodes than women who were out. Comparatively it was found that men who were in the closet were less likely to report a depressive episode than those out of the closet. Along with effects on the mental and physical health of those who remain in the closet, it also impacts the cost of health care and the public awareness of the LGBTQ community.
Statistics.
A 2019 study by the Yale School of Public Health estimated that 83% of LGBT people around the world do not reveal their sexual orientation. According to a 2020 survey by the European Union Agency for Fundamental Rights, 30% of LGBT people in the EU are very rarely or almost never open; the highest percentages are Lithuania (60%), Bulgaria (54%), and Romania and Serbia (both 53%). In China, a 2016 survey found that 85% of LGBT people have not told anyone about their sexual orientation and 95% have not revealed it outside their family. In the United States, 4% of gay and lesbian people and 26% of bisexual people are not "out" to at least one of the important people in their lives.
References.
Other sources