Closeted is a term that refers to an individual who has chosen to keep his or her sexual orientation or gender identity a secret or undisclosed. The term closeted usually refers to individuals in the LGBT community. When an individual is closeted, they are often referred to as being "in the closet."
More About Closeted
Those who are closeted will often choose not to disclose their sexual behavior and preference for fear of being persecuted or discriminated against. Although the term closeted can have negative implications, not all individuals who are in the closet choose to do so for negative reasons.
When a closeted individual of the LGBT community does choose to disclose their sexual orientation, it is called coming out — as in coming out of the closet.