Definitions
1.adjective(possibly obsolete) Happy, joyful, and lively."The Gay Science"
2.adjectiveQuick, fast.
3.adjective(possibly obsolete) Festive, bright, or colourful."Pennsylvania Dutch include the plain folk and the gay folk."
4.adjectiveSexually promiscuous (of any gender), (sometimes particularly) engaged in prostitution.
5.adjectiveHomosexual:
6.adjectiveA pejorative:
7.adjective(of a dog's tail) Upright or curved over the back.
8.adjective(possibly obsolete) Considerable, great, large in number, size, or degree.