When one person feels they have a rivalry with another far superior person. The superior person usually doesn't know about it or feel that the little brother is any kind of a threat. The little brother usually puts forth maximum effort in meaningless situations in order to get the feeling of a win over his rival.
The Baltimore Raven's fans have little brother syndrome. They think they are the Redskin's rivals.
by persephone81 August 13, 2009
Following around friends like a clingy younger brother. One with said syndrome cannot make decisions for or take actions by himself. Usually acts like a fake-ass punk and/or lil bitch.
I walked into the other room and he followed me. So I went back into the livingroom and, sure enough, he came in a minute later. Fool wouldn't even go to that girl's house by himself. He's got a bad case of little brother syndrome.
by Not your brother! April 9, 2009
When an older sibling brings a best friend into their home and the littler sibling thinks said person is their new friend and tries to impress them/flirt/or just won't leave you too alone for any reason
Your little brother has "Little Brother Syndrome" when he keeps trying to show your best friend his vast collection of Hot Wheels, even though said friend doesn't care and you both want him to go away.
by Dr. Upin Disbich July 5, 2015
When a person(doesn't always have to be a sibling) idolizes something you have done and decides to follow in your footsteps, ultimately copying exactly what you have done; complete and juvenile lack of originality.
My friend has little brother syndrome. I began to pursue my dream of writing comic books, and not to my surprise, i find the hack doing exactly the same.
by xX Unwise Xx January 13, 2010
When mom makes you play with your little brother but he sucks at everything.
Mom said its my turn on the xbox! Thats little brother syndrome!
by Harligan December 8, 2019
An ingrained fear reaction that younger siblings show towards an elder. If properly nurtured can result in reactions such as flinching when the older sibling walks past even though the younger is taller, bigger and stronger and 18+. This can also result in a defeatist attitude and outcome when in confrontations with the older sibling.
Luke was a victim of little brother syndrome. Even though he was bigger, stronger, faster and a black belt in karate he could never defeat his older brother in a tickle fight. Luke is 20 years old.
by Rincow April 15, 2011
A person that is really good at being a goof ball and breaking the tension of situations through comedy and playful antics. But at the same time, has a hard time ever taking things seriously or taking responsibility for things, expecting or assuming others will simply come to help out when needed. This is often how little brothers can behave, hence the term.
Sean is always getting parking tickets, and it's 'never his fault.' I used to feel bad, but now I just laugh at him. His older brother doesnt get it, and his mom just always bails him out. I don't get the guy, but he's a blast to be around. He has total little brother syndrome.
by wawaone February 12, 2011