an effort or persuasion that has almost no effect; a futile or wasted attempt.
彼にいくら説明しても、暖簾に腕押しだった。
No matter how much I explained to him, it was like pushing against a shop curtain—completely ineffective.
古い制度を変えるには、一人二人の努力では暖簾に腕押しだ。
To change an old system, the efforts of one or two people are like pushing on a curtain—futile.
説得し続けたが上司には響かず、暖簾に腕押しに終わった。
I kept trying to persuade him, but it didn't resonate with my boss and ended up being a waste of effort.