Little Brother Syndrome 

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.

Little Brother Syndrome by Rincow May 4, 2011

Little Brother Syndrome 

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.

Little Brother Syndrome by Dr. Upin Disbich July 19, 2015

Little Brother 

The most annoying people in the history of time, always gets away with everything. Thinks they’re the best person ever.

Sister: “Oh my god! Did you see my little brother Azlan today??”
Friend: “Yes! I don’t know how you can live with your little brother, Xara!!”
Sister: “I know right, I’m so glad I’m leaving for college in a few years!!”

Little Brother by SuperiorSibling August 6, 2019

Little brother syndrome 

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.

Little brother syndrome by xX Unwise Xx January 12, 2010

Little Brother Syndrome 

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!

Little Brother Syndrome by Harligan December 8, 2019

Little Brother 

The younger, dumber, incompetent version of Big Brother. (referenced in George Orwell's 1984) Claims to have control over society, but is really a bumbling idiot.

Little Brother was responsible for allowing a man to fly cross-country with an expired boarding pass and nobody stopped him at one of the many checkpoints along the way.

Little Brother by Mykl66 July 11, 2011

little brother fetish 

Wanting sex from little brothers of her current mate

Kristen has a little brother fetish!

little brother fetish by Dictionary.com March 26, 2003