天てんに向むかって唾つばきを吐はく

expression, godan verb (-ku)

to cut off one's nose to spite one's face; to harm oneself by trying to harm others

Idiomatic expression meaning that an attempt to harm someone else backfires and ends up hurting oneself. The literal image is spitting toward the sky and having it fall back on you.

See also: 天に唾する

• 彼かれを陥おとしいれようとしたが、結けっ局きょくは天てんに向むかって唾つばきを吐はくようなものだった。

  He tried to bring him down, but it was like cutting off his nose to spite his face.

• そんなことをすると、天てんに向むかって唾つばきを吐はくことになるよ。

  If you do that, you'll end up harming yourself.