adjective Non-heterosexual or non-cisgender: homosexual, bisexual, asexual, transgender, etc.
adjective Pertaining to sexual or gender behaviour or identity which does not conform to conventional heterosexual or cisgender norms, assumptions etc.
the queer community
adjective Strange, odd, or different; whimsical.
adjective Slightly unwell.
I felt queer after eating those shrimp.
adjective Drunk.
noun A person who is or appears homosexual, or who has homosexual qualities.
noun A person of any non-heterosexual sexuality or sexual identity.