also: かべぞしょう
noun
grumbling to oneself; muttering to oneself
Refers to complaining or talking to oneself, often when alone or when others are not listening. The literal meaning is 'wall lawsuit', evoking the image of arguing with a wall.
彼はいつも壁訴訟をしている。
He is always grumbling to himself.
誰も聞いていないのに、壁訴訟を繰り返していた。
Even though no one was listening, he kept muttering to himself.
独り言 is a more common and neutral term for talking to oneself, while 壁訴訟 carries a nuance of complaining or grumbling, often with a sense of futility.
Compound of 壁 (wall) and 訴訟 (lawsuit). The term figuratively describes the act of complaining to oneself as if arguing a case against a wall, implying that no one is listening.