What's the meaning of 厨 in internet slang?

I am not so sure about the details on how this word originated. Of course it is the a loanword from Japanese, and it is a substitution of 中, but I am not so sure which exact word that including 中. In 萌百 it says from the word 中坊(Japanese) that means middle school, which is the same as Tang's answer because the 中 in 中二 means middle school.

But the usage is very clear. X厨 means insane fan(s) of X. The focus is the "insane" part. In the beginning it is a negative word. Some one accuse others to be too crazy about an idol/work. But later on it is used by the fans themselves indicating that they enjoy the idol/work so much and would like to be crazy.

For now, it is tend to be a neutral word, and just means "fan" and less stress on the "insane" part, but be careful that this usage is only when speaking of oneself. If you say "I am a X厨." It can mean merely "I am a (normal) fan of X", or "I sickly love X." (as Kevin's answer said) But if you say "This guy is a X厨." it is somewhat offensive.

In Japanese:

厨 (chu)

sounds the same as the first character of

中毒 (chudoku)

And 中毒 means sickly loves sb/sth. So "XX厨" basically means 'someone who sickly loves XX'. E.g. I'm a Gakki厨. I would do anything for her, including suicide.

一个普通的《X》厨

I might be wrong. My first impression is that it can be analogous to 她还是个"厨", meaning she is still virgin. So, I might think 一个普通的《X》厨 means he/she doesn't have much experience or knowledge about 《X》( not as much knowledge/experience as a normal fun has).

厨二病

Japanese

Etymology

Derived by replacing the 中 (chū, “middle [school]”) with 厨 (chū, “freak; nerd”).

厨二病 (hiragana ちゅうにびょう, rōmaji chūnibyō)

Alternative spelling of 中二病

This usage of 厨 here came from Japanese 'ちゅう' (kanji: 厨 ). Which means "freak or nerd"

"XX 厨" = "XX nerd" or "XX freak". Anime and manga fans would be familiar with this term

Other Japanese terms imported to Chinese via manga (mostly circulated among manga readers in written form)

• 醬(ちゃん).

"XX 醬" = "XX 小妹妹" (Dear little XX)

• 宅(taku) came from Otaku (a young person who is obsessed with computers or particular aspects of popular culture to the detriment of their social skills..)

"XX 宅" = "XX obsessed" e.g. "軍事宅" means "a person obsessed with military"