Hey Everyone! 
Today we will be covering the internet slang 厨二病.
Any idea what this one means?
久しぶりに let’s do a word break-down.
厨
食物を調理する場所。 台所。
A place where you prepare food. Kitchen.
二
ものの個数を数える時の、一の次の、すなわち１に１を足して得る数（に等しい数や順位）。
When counting, the number that comes after 1. In other words, a number you get when you add 1 and 1.
病
体を悪くする。わずらう。
To get sick. Sickness
That probably made it more confusing, didn’t it? This is actually just an alternate spelling of the word of 中二病.
So… what is 中二病？
This uses the kanji 病 so it must be a disease, right? Although it does use the word 病, this is not a medical condition, nor is it a disease. The 〜病 used here is there simply to emphasize that the person that this word describes has the tendency to act like a 中二.
中二? Whats that?
This is simply an abbreviation for 中学2年生.
So, what do we get when we put both of these words together? We get a word that means ‘a person who acts like an 8th grader’ or a more direct translation would be ‘8th grade disease’. This word is used to describe people that talk or act as if they are still in middle school. It is sometimes used in a self-deprecating way when the speaker does something embarrassing.
You might be asking, why 中二? Why not 中一 or 中三? The reason for this is because stereotypically, kids in 8th grade (at least in Japan) gain a bit of self-confidence (whether it’s real or fake) and will do and say things to stand out of the crowd for ‘cool points’ since they are no longer in a transitioning period (from 6th to 7th grade), and they are not busy with studying for exams like kids in 9th grade.
Origin 
This sounds like something that would have started on the internet, but surprisingly, this word originated on a radio show called 「伊集院光（いじゅういんひかる） 深夜（しんや）の馬鹿力（ばかぢから）」. In one of the episodes, the host, Ijuin Hikaru said,
「自分（じぶん）が未（いま）だ中二病（ちゅうにびょう）に罹患（りかん）している」(I am still suffering from 中二病).
After this statement, the word 中二病 caught on, and soon after, a new segment started on the show that talked about embarrassing adolescence behaviors sent in by the listeners.
厨二病 
So where does this spelling come from?
This spelling originated in…you guessed it! 2ch!
Once this word caught on, people on the internet started to use it to describe people that would respond in an immature way, and people that bragged about themselves in an immature (kid in middle school-ish) way.
Before this slang caught on, these kind of people were simply called a 中坊, which was an abbreviation for 中学生の坊や. However, the netizens of 2ch started to use the word 厨房 instead because it is pronounced the same.
So, when 中二病 caught on, they simply changed the first kanji to 厨 to match the pre-existing slang 厨房.
Characteristics 
So, I’ve talked about ‘immature language’ and ‘immature actions’, but what exactly does that mean?
Basically these ‘immature’ behaviors would include anything a kid in middle school might say or do to stand out to be cool, unique, edgy, etc.
Here is a quick list of things that are considered a sign of suffering from 厨二病:
- Liking edgy things
- Things like violence and gore
- Uses words like 闇 and 死 in their user names
- Wearing bandages to look cool
- Pretending to be their favorite character (in daily life)
- For example: Sitting and talking like L from Death Note (This was huge when I was in school. It was cringe then, it is cringe now…of course unless you are cosplaying or something)
- Using strong language on the internet (for example, people that talk big online, but in real life you know they do not act that way)
- Saying things like ‘I have no emotions’ or ‘I don’t feel pain’
- Claims to have a second personality they are hiding
- Wants to be a ヤンキー
- And many more!
A lot of these are things are what a lot of Japanese people expect an ‘edgy’ teenager would say and do to stand out from the crowd. When kids do these, it is embarrassing, but at the same time it is endearing since we have all been through a phase like that. However, when we see grown adults acting similarly to 8th graders, it is a bit painful to watch.
This word is similar to how the word ‘cringe’ is used on the internet, but with 厨二病 it has an extra nuance of calling a person an insecure 8th grader.
Although it may sound very derogatory due to the fact that it uses the kanji 病, it does not have a very derogatory nuance like some other words used on the internet, and it is usually used as a light jab at someone.
このブログ書いてたら中二の頃にしたことが蘇ってきた。やばい。俺をひとりにしないでくれ、みんなも中二の頃にした恥ずかしいことを思い出せ！
Fuga
If you missed the previous posts, you can check them out here!