Meg-John Barker

The original meaning of “queer”, in 16th-century English-speaking countries, referred to something strange or illegitimate, as in “there’s nowt as queer as folk” or being “in queer street”, meaning someone having financial difficulties.
Using queer to mean odd, in the 19th century, social reformer and founder of the cooperative movement, Robert Owen, famously said to a colleague: “All the world is queer save thee and me, and even thou art a little queer.”

in Arthur Conan Doyle’s Sherlock Holmes stories. There’s also the American phrase “queer as a three dollar bill”, from a similar time, suggesting something odd and suspicious

The earliest recorded use of “queer” as a form of homophobic abuse is said to be an 1894 letter by John Sholto Douglas, the Marquess of Queensberry. He was the father of Alfred Douglas and famously accused Oscar Wilde of having an affair with his son.
“Queer” quickly became a derogatory term for same-sex sex, or for people with same-sex attractions, particularly “effeminate” or “camp” gay men.