Means a man, likes a man, or a boy, likes a boy.
Boy 1: Ayy bro, I think I like boys..
Boy 2: Oh so your gay?
Boy 1: Yup!
Anything related to jojo bizarre adventure
Person 1: I love jojo bizarre adventure
Person2: your gay
Gay has two general definitions.
One definition is simply "happy."
The second is a term for homosexuality.
"I'm feeling very gay today." (good for both definitions!)