Gaydar.

About Gaydar

Gaydar is a colloquialism referring to the intuitive ability of a person, especially a queer person, to assess others' sexual orientations as homosexual, bisexual or straight. Gaydar relies on verbal and nonverbal clues and LGBT stereotypes, including a sensitivity to social behaviors and mannerisms like body language, the tone of voice used by a person when speaking, overt rejections of traditional gender roles, a person's occupation, and grooming habits. Similarly, transdar refers to the ability for trans people to recognize trans people who pass well, by subtle cues such as "the size of the hands and wrists".