YOU SAID:
slapping a dead horse
INTO JAPANESE
死んだ馬を叩く
BACK INTO ENGLISH
beat a dead horse
INTO JAPANESE
死んだ馬を倒す
BACK INTO ENGLISH
kill a dead horse
INTO JAPANESE
死んだ馬を殺す
BACK INTO ENGLISH
kill a dead horse
That didn't even make that much sense in English.