Gay is a term that primarily refers to a homosexual person or the trait of being homosexual. The term was originally used to refer to feelings of being "carefree", "happy", or "bright and showy". The term's use as a reference to homosexuality may date as early as the late 19th century, but its use gradually increased in the 20th century. In modern English, gay has come to be used as an adjective, and as a noun, referring to the people, especially to males, and the practices and cultures associated with homosexuality.
By the end of the 20th century, the word gay was recommended by major LGBT groups and style guides to describe people attracted to members of the same sex. At about the same time, a new, pejorative use became prevalent in some parts of the world. In the Anglosphere, this connotation, among younger speakers, has a derisive meaning equivalent to rubbish or stupid (as in "That's so gay."). In this use, the word does not mean "homosexual", so it can be used, for example, to refer to an inanimate object or abstract concept of which one disapproves. This usage can also refer to weakness or unmanliness. When used in these ways, the extent to which it still retains connotations of homosexuality has been debated and harshly criticized.
The word gay arrived in English during the 12th century from Old French gai, most likely deriving ultimately from a Germanic source. For most of its life in English, the word's primary meaning was "joyful", "carefree", "bright and showy", and the word was very commonly used with this meaning in speech and literature. For example, the optimistic 1890s are still often referred to as the Gay Nineties. The title of the 1938 French ballet Gaîté Parisienne ("Parisian Gaiety"), which became the 1941 Warner Brothers movie, The Gay Parisian, also illustrates this connotation. It was apparently not until the 20th century that the word began to be used to mean specifically "homosexual", although it had earlier acquired sexual connotations.