Gay is a word used to describe someone who is homosexual. Today, the word usually means a person who is sexually attracted to people of the same sex. They are often also romantically interested in people of the same sex. This means males who like other males or females who like other females. The word "gay" can mean any homosexual person, but sometimes it specifically means homosexual men. Homosexual women are sometimes called "lesbian" instead.
Negative use of the word gay
Most people in the gay community use "gay" only when talking about gay people. Outside the gay community, it is sometimes used as slang by young, illiterate, insensitive, and bigoted people to mean something is weak, stupid, or less important. For example, "That is so gay!" is used to say something looks or acts stupid. They may also use the word "queer" in the same way. This is considered immature and is not often used by adults. It is also considered offensive to homosexual people.
Sometimes people also use this to mean something is very colorful. This is because of the original meaning of the word. Sometimes even gay people themselves use the word this way.