Kinsey 6, n. — Green’s Dictionary of Slang

Kinsey 6 n.

[the categorization by sexologist Alfred Kinsey (1894–1956) in his book Sexual Behavior in the Human Male (1947), popularly known as the ‘Kinsey Report’]

(US gay) a person who is completely homosexual, as opposed to one with some bisexual inclinations.

1999

Gaymart.com Queer Sl. in the Gay 90s 🌐 Kinsey Six – A person who is completely homosexual, as opposed to one with some bisexual inclinations.