Creepyis used to describe things that seem scary or supernatural, like old empty houses or ghost stories. But for many English speakers, it is even more common to use this word for people whose behavior makes others feel uneasy or even threatened. This usage is especially common in informal conversation.
Last week's Word of the Day "awkward" also can describe behavior that isn't socially normal or expected. However, creepy behavior is not just strange but also usually repulsive in some way and can sometimes, but not always, cause people to feel scared. In certain cases, creepy is also used for behavior that is sexually predatory. You could say, "It was awkward when Taylor went to the Halloween party without a costume." But, "It was creepy when Taylor spent the entire night standing outside the house and looking in the windows at the party instead of going in."
creep (noun): This word refers to a person—often but not always a man—who has unsettling or strange behavior. Example: "That guy at the bar wouldn't stop bothering me, even when I told him to leave me alone. He's a creep!"