... is when a guy and a girl are very good friends, and extremely close, spending most of their time together. Eventually, the girl says "I think I love you", or in some way tries to make the relationship a physical one, and the guy simply doesn't feel about her that way, because he "Thinks of her as a sister."

Hence: The Sister Syndrome
Girl: Listen, Guy, I think I want to make our relationship between us a romantic one, I want to be more than just friends.

Guy: Ew! Sorry hun, I think we've got a case of Sister Syndrome!
by Russell Bishop May 09, 2007

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from daily@urbandictionary.com. We'll never spam you.

×