This is note I found while looking for the meaning of the word gay. This note explains the origins of the word and uses throughout history.
"In addition to its original and continuing senses of “merry, lively” and “bright or showy,” gay has had various senses dealing with sexual conduct since the 17th century. A gay woman was a prostitute, a gay man a womanizer, a gay house a brothel. This sexual world included homosexuals too, and gay as an adjective meaning “homosexual” may go back to the late 1930s. After World War II, as social attitudes toward sexuality began to change, gay was applied openly by homosexuals to themselves, first as an adjective and later as a noun. Today, the noun often designates only a male homosexual: gays and lesbians."”
Taken from Dictionary. com app.