Gaydar
Gaydar (a portmanteau of gay and radar) 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.