A gaydar is a built in radar allowing people to distinguish homosexuals from a large group of hetrosexual people. It is often found, however, that the gaydar of a hetrosexual person works far better than that of a homosexual.

The ability/gift of being able to detect homosexuality in other people.

GAYDAR. Short for Gay-Radar. The ability to tell when someone near you is homosexual, even if they have given no obvious indications of being so. This is an ability usually possesed by homosexuals and their fag-hags.
It's like Spiderman and his Spider sense. He can just "feel" when there is danger nearby. Gaydar allows you to "feel" when there is gayness nearby.

A sense that allows for someone to detect homosexuality in another

Similar to Spidermans Spidey-sense, except where Spiderman's spidey-sense detects imminent danger, a gaydar detects a homosexual nearby, either thru hearing the tone of one's voice or observing the style of their movement, which sets off the realization that this person may prefer members of the same sex. (Being a homosexual, deal with the definition, because most should defend this one!)

The gift of being able to sense the homosexual vibe.

Extended form : Gay Radar

The amazing ability to sense gay or bi (tho mostly the first) by apperence, personality, how they talk, move breathe, practically how they sleep.

Usually the gay/bi ones are always the good looking ones. ie: Nick Lachey, David Beckham, Channing Tatum, Ryan Carnes, Chad Michael Murray

and usually the ugly one's are hetero.
ie: Dick Chaney, George Bush and Bill O Reily (sad isn't it)

A person's ability to tell if a person is gay/homosexual/flamer etc.