Chuunibyou 

A Japanese slang term which roughly translates to "Middle School 2nd Year Syndrome". People with chuunibyou either act like a know-it-all adult and look down on real ones, or believe they have special powers unlike others.

This is a common stage in growth; for most people, it happens--you guessed it--around the 2nd year of middle school (Grade 8 in Japan). However, the problem is, there are some grown-ups who have this symptom.
There are 3 main types of Chuunibyou. DQN-type pretends to be antisocial even though they aren't, or can't be and has made-up stories about antisocial behavior. Subculture-type prefers subculture or minor trends just to be different and have the "cool" factor. Evil Eye-Type admires mystical powers and pretends to have one of their own, to the extent of establishing an alias just for that.
And if you think you have one of these or want more information in the subject, a good idea is to read the "Chuunibyou User Manual" (中二病取扱説明書, Chuunibyou Toriatsukai Setsumei Sho) by Saegami HYŌYA.

If you tl;dr I'm going to clobber you.

An example of DQN Chuunibyou:
"Look at all those bandages wrapped around you! What happened?"
"I had a bunch of gang fights."
"Come on, I know you're too kind to be a gangster."

An example of Subculture Chuunibyou:
"When I collect Pokémon cards, I only collect ones that are imported from Japan."
"Can you read all those?"
"-_-; S-sure I can..."

An example of Evil Eye Chuunibyou:
"Don't take that bandana off my left wrist. It's sealing an evil spirit inside me and if you take it off I may go berserk."
"Dude, calm down. You just have chuunibyou."

Chuunibyou by cutesy pastel living doll August 7, 2012

Chuunibyou 

A Japanese term for cringe. It occurs in the second year of middle school, aka 8th grade. It makes you wanna die if you ever remember it.

(Idk maybe it is a real mental illness, idk I went through it too)

It makes you think that you are special, you are powerful, etc, when in reality you're just going through a cringe fest.

Also, you aren't the god of something or have dark powers or whatever,you're just a dumb kid who went through this hell..

Normal kid: Hey, you wanna come to the after party?

Chuunibyou kid: No, resent you peasant. I hath to tend to my right arm, which holds the power of the god of hentai, gigguk, yeah blah blah blah---

Normal kid: *visible disgust*

Chuunibyou by Pseudonym for my name July 2, 2021

Chuunibyou Demo Koi ga Shitai 

Also known as Love, Chunibyo and Other Delusions it is an amazing anime filled with romance, drama, comedy and action. Its the best anime.

Person 1:Hey, have you seen Chuunibyou Demo Koi ga Shitai!
Person 2:Yes, Its the best anime ever!

Chuunibyou Demo Koi ga Shitai by Van!shment February 19, 2021

chunibyo 

A diasese that develops around when you are in middle school where you believe you have powers such as dark magic or special abilities such as being able to use "magic" items

"I think you have chunibyo"

chunibyo by Goood kkooom April 21, 2017

chunibyo 

Also spelled "chuunibyou" is when you feel you are special, or superior to everyone around you due to the way of the universe or the laws of magic.

Cecile: Why is Allie always acting like she's battling someone?
Becky: She has severe chunibyo!

chunibyo by itssojuvia October 7, 2021

Chuunibyo 

Chuunibyo is a Japanese slang term that is used when referring to young teens(middle schoolers in particular) who are highly influenced by games and Japanese anime. This strong influence causes them to act as if certain concepts from fictional mediums are also applicable to the real world.

"Man why is (name) always act like someone out of a fantasy world. He's acting like a total chuunibyo."

Chuunibyo by bigafrocj July 4, 2021