Beating a dead horse
tʃaɪniːzle̞tə ɴ tä dʒapəniːzle̞tə tʃaɪniːzle̞tə o̞ tʃaɪniːzle̞tə kɯᵝ ɛs eɪtʃ aɪ ɛn diː eɪ juː ɛm eɪ əʊ tiː eɪ tiː eɪ keɪ juː
In Japanese 死んだ馬を叩く (shinda uma o tataku)
This idiom is a direct translation, emphasizing the futility of continuing an action.
Example
"もう議論しても無駄だよ、死んだ馬を叩くようなものだ。(Mou giron shite mo muda da yo, shinda uma o tataku you na mono da.)"
