The adjective queer means "unusual" or "peculiar," or sometimes "suspicious." The main character in a creepy novel might decide to investigate the queer noises she hears coming from the attic in the middle of the night. Uh oh.
Like many words, queer has many meanings. One is "odd," as in "I feel kind of queer today." In the 20th century, queer also began to be used as a slur for members of the LGBT community; although use of the word is still controversial today, it has been widely reclaimed as a positive or neutral term. Many universities have Queer Studies programs, for instance. As a verb, queer can mean "to endanger or expose to risk", and also "to hinder, thwart, foil, or baffle."