Gaydar
Gaydar (a portmanteau of gay and radar) is a colloquialism referring to the intuitive ability of a 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.
The detection of sexual orientation by outward appearance or behavior is challenged by situations in which masculine gay men do not act in a stereotypically gay fashion, or in which metrosexual men (regardless of sexuality) exhibit a lifestyle, spending habits, and concern for personal appearance stereotypical of fashionable urban gay men. For women, a tomboy might be mistaken for being butch, or a gay woman might act and appear in traditionally feminine ways.