Nimrod. In Genesis, he’s recorded as being a hunter of legendary renown and expertise. But I remember the first time I read that for myself thinking, “Really? I thought it meant ‘idiot.'”
The etymologists can’t document exactly how this change in meaning happened, but they do know that it happened within the last 30-40 years, taking on the connotation of “klutz, geek” etc.
Popular opinion is that the change is actually thanks to a misunderstanding of–get this–a Bugs Bunny cartoon. 🐰See, Bugs would occasionally sarcastically call Elmer Fudd “a regular Nimrod.” Meaning, of course, that he’s not living up to the famous hunter’s name. But people unfamiliar both with hunting and with the biblical figure assumed he was just insulting Fudd in a straight-up, not-sarcastic way. So Nimrod became a way to insult anyone as unskilled as Fudd…rather than a way to point to an expert hunter.🐰