In gay slang, a beard is a female companion used to hide a gay man's sexuality by appearing in public as if she and the gay man were a heterosexual couple. To do this with a heterosexual woman without letting her know you are gay is generally considered poor form. The term originated in the mid-1960s. It is derived from the notion that a man with a woman on his arm looks more butch, like a man with a beard. A male companion who accompanies a lesbian woman for the same purposes is sometimes called a merkin.

Closeted gay men and lesbians may also take part in this kind of relationship, to their mutual advantage. In the past a great many gay men and lesbians married in order to fit in with heterosexual society – this practice continues today, but less so, as the gay rights movement has made society more accepting of "out" gay men and lesbians.

In the 1920's this union was sometimes referred to as a Lavender marriage.

This term should not be confused with fag hag.

In Woody Allen's film "Broadway Danny Rose", Allen's character insists he is only 'the beard' and not a boyfriend when confronted by gangsters while he escorts Tina (played by Mia Farrow).

The television show Seinfeld brought this term into mainstream awareness by titling an episode "The Beard" in which Elaine Benes helps a homosexual friend hide his orientation, and eventually tries to convert him.

LGBT argot