Sister Syndrome 

... 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!

Sister Syndrome by Russell Bishop May 24, 2007

Little Sister Syndrome 

In which a guy tells a girl who's obviously got the hots for him that he "thinks of her as a sister" or "she's a little sister to him," so as to blow her off lightly.
This is sometimes considered offensive and rarely considered an actual compliment, as the girl usually knows that this means that he doesn't see her as date-able.
Used frequently on friendly yet ugly girls.

Sam: Oh, Bertha, you're so cute!
Bertha: Really, you think so?
Sam: Oh yea; you're like a little sister to me!"
Bertha: Oh...

*later*

Sally: Sam complimented you?
Bertha: Yea, but then he ruined it via little sister syndrome.
Sally: Jerk.

Little Sister Syndrome by andi844 August 22, 2007

little sister syndrome 

When the younger sister of an older sister is more attractive than the latter

Laura is hot but her sister Rachael is infected with little sister syndrome.

little sister syndrome by 4pumpwonderchump July 15, 2009

Younger Sister Syndrome (YSS)

When the older/oldest sister of a family oftens engages in a relationship out of spite of her already engaged or further advanced younger sister. Generally moves in with her new man, gets engaged, married or pregnant all within the span of the younger's term of engagement. In the long run, not a wise decision.

Most people have witnessed at least two of these instances. General outcomes of "YSS" include but are not limited too:
1. a jailed husband (physical abuse, drugs, theft, video taping women at work, etc..)
2. A miserable 6 month marriage
3. single motherhood
4. self pity

Observer #1: "Jamie moved into her man's house, got pregnant and has quit her high paying job all since her younger sister LeAnn got engaged to her her long time boyfriend."

Observer #2: "yeah, I heard her man has a ton of great qualities like...well, umm...nevermind. At least he drives a nice truck"

Observer #1: " Another victim of the Younger Sister Syndrome (YSS)"

Younger Sister Syndrome (YSS) by it's funny...unless it's you July 12, 2008

Step-Sister Syndrome 

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.

Originates from Cinderella.

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

Step-Sister Syndrome by Seraphim14 April 14, 2010

Big Sister Syndrome

When you have always been the one to pick on your siblings with no consequences... and therefore as an adult shamelessly poke at others even when you shouldn’t. Specially when an adult female poked fun and teases others because they never had an older sibling to put them in their place.

My girlfriend won’t stop trying to tickle me when we cuddle and finds it funny. It’s like she has big sister syndrome. Little does she know what’s coming!

Big Sister Syndrome by Bigsistersofurban February 9, 2021

little sister syndrome 

when a girl feels like she annoys everyone she talks too, the fear of being seen as an irritating burden

Sarah has an awful case of little sister syndrome, she wont tell me what’s going on

little sister syndrome by cemeterydoll November 30, 2022