A Homosexual who hasn't told anyone about his/her sexuality.

A person who is either A: Someone who is gay or bisexual and afraid to show it in public or B: Gay and tries to hide it by calling other people gay to seem 'cool' (straight).

Ryan Seacrest.

Someone who isn't yet out about them being a homosexual.

A gay person who wants to keep their true sexual orientation
a secret.
A homosexual who will make a big show of dating the opposite sex to hide their gayness.
A fag who can't or won't accept the truth about thier sexual
desires.
A person who looks and acts like a queer but has an army of deniers to defend his charade.
Justin Bieber.

A special breed of Homo, often considered extremist in their behavior and responses to people who believe they are gay. There are many Closet Homosexuals in the world who, through acceptance and respect by their peers, end up coming out of the closet; however, the Airtight Closet Homosexual tends to deny the fact that they are gay 100% of the time every time they are suspected as such.

When somebody acts homophobic but is really gay they only let their good friends know that they're gay