遣り損なう

プログレッシブ和英中辞典(第4版)

やりそこなう【^▲遣り損なう】

fail ((in))

候補者は票読みをやり損なった
The candidate was wrong in his prediction of the vote.／The candidate miscalculated the number of votes he would receive.

仲裁をやり損なった
He failed in his attempt to mediate.

今度やり損なったらおしまいだ
If I don't succeed this time, it's all up with me.

手袋を編もうとしてやり損なった
She made a mess of her attempt to knit gloves.

出典　小学館「プログレッシブ和英中辞典(第4版)」