"gay" in that sense is a pejorative against homosexual people. You could almost make it work with the original definition though.
From Wikipedia -
> Gay is a term that primarily refers to a homosexual person or the trait of being homosexual. The term originally meant 'carefree', 'cheerful', or 'bright and showy'.
From Wikipedia -
> Gay is a term that primarily refers to a homosexual person or the trait of being homosexual. The term originally meant 'carefree', 'cheerful', or 'bright and showy'.