Uncanny /ʌnˈkani/ adjective strange or mysterious, especially in an unsettling way.

Uncanny went on a journey. In the late 1500s, it started as "mischievous, malicious." By the 17th century, in Scotland and northern England, it had shifted to "careless, incautious; unreliable, not to be trusted", built from un- "not" + canny, which once meant "skilful, prudent, lucky," a sibling of today's cunning. Canny also carried the idea of being superstitiously lucky, skilled in magic. Its opposite inherited that shadow.

Wright's English Dialect Dictionary (1900) lists two senses for uncanny as used in the North: first, "awkward, unskilful; careless; imprudent; inconvenient." Second: "unearthly, ghostly, dangerous from supernatural causes; ominous, unlucky; of a person: possessed of supernatural powers." By the 1800s, it had settled into common English with a broader sense, supernatural character, weird, mysterious, strange.

It never fully resolved. Which is fitting.

Not weird in a good way. Not weird in a bad way. Weird in the way that makes you check twice, once because something is off, once because you can't name it.

Borges called it untranslatable. The German unheimlich comes close, unhomely, the familiar turned slightly wrong. But uncanny has an older edge: it belonged to Scotland first, to people who were not quite safe to trust or deal with through association with the supernatural. Not monsters. Just people you couldn't fully account for.

"Walking through a plant biologist's lab, I pass a four-metre plant that looks straight out of Jack and the Beanstalk. The biologist barely breaks stride: "Ah, yes, tobacco plant. We accidentally knocked out the growth regulation gene." That's uncanny." 

From Jannis, Fellow Researcher and Friend