A girl who is very attractive
but due to more attractive
sister(s) or long term friends has not gotten exposed to people thinking she's hot since they all go for the sister or friend. Usually consider themselves ugly and like
in Ugly Duckling Syndrome have good
personalities and will date any guy because "Looks aren't important" and they have a good
sense of humor.
Aaron: Amy you're hot
Amy: No I'm not, my sisters are and I got the shitty genes
Aaron: Want to come over later?
Amy: Sure, your funny.
Aaron: Hurray for Step-Sister Syndrome