stranger

Not normal; odd, unusual, surprising, out of the ordinary.

"He thought it strange that his girlfriend wore shorts in the winter."

Unfamiliar, not yet part of one's experience.

"I moved to a strange town when I was ten."

Having the quantum mechanical property of strangeness.

A person whom one does not know; a person who is neither a friend nor an acquaintance.

"That gentleman is a stranger to me.  Children are taught not to talk to strangers."

An outsider or foreigner.

One not admitted to communion or fellowship.

To estrange; to alienate.