noun
summer newbie; summer noob
Derogatory internet slang for a young, inexperienced user who joins an online community during summer break, often seen as disruptive. The English gloss 'summerfag' is a direct but highly offensive translation; the Japanese term is also derogatory but less taboo.
夏厨が増えると掲示板の質が下がる。
When summer newbies increase, the quality of the forum goes down.
あの書き込み、完全に夏厨だな。
That post is totally from a summer noob.