expression, suru verb (special)
harm oneself by trying to harm others; cut off one's nose to spite one's face
Idiomatic expression; literally 'to spit at the sky', meaning that an attempt to harm someone else backfires and hurts oneself instead.
彼を陥れようとしたが、天に唾する結果になった。
He tried to bring him down, but it ended up being a case of cutting off his nose to spite his face.
そんなことをすれば天に唾するようなものだ。
Doing that would be like spitting at the sky.