harebrained idea

cliché Some idea or plot that is or seems laughably foolish, absurd, or unrealistic. A: "Hey, Paul, listen to this! I've got a great idea to get rich!" B: "Here we go again, another one of your harebrained ideas!" Am I going crazy here, or has everyone else just lost their minds? Because this is the most harebrained idea I've ever heard. Only a fool would get sucked into one of Richard's harebrained ideas.

harebrained scheme

cliché Some plan or plot that is or seems laughably foolish, absurd, or unrealistic. A: "Hey, Paul, listen to this! I've got a great idea to get rich!" B: "Here we go again, another one of your harebrained schemes!" Am I going crazy here, or has everyone else just lost their minds? Because this is the most harebrained scheme I've ever heard. Only a fool would get sucked into one of Richard's harebrained schemes.