noun
social media account for posting negative or depressive content
Internet slang. Refers to a separate account (often anonymous) used to vent, complain, or share mental health struggles, distinct from one's main account.
病み垢で愚痴を吐き出す。
I vent my complaints on my vent account.
彼女は病み垢にネガティブな投稿をしている。
She posts negative things on her vent account.
Compound of 病み (yami, 'illness' or 'mental darkness') and 垢 (aka, internet slang abbreviation of アカウント 'account'). The kanji 垢 is ateji for アカ.