From Longman Dictionary of Contemporary Englishhare-brainedˈhare-brained adjective STUPID/NOT SENSIBLEa hare-brained plan or idea is very silly or unlikely to succeed his latest hare-brained scheme
Examples from the Corpus
hare-brained• Self magazine has a hare-brained interpretation in its current issue.• This Government's many imaginative and effective initiatives are far more helpful to the regions than any hare-brained scheme from Labour.• Alice had to figure out how to pay the rent after Ralph spent the money on another of his hare-brained schemes.• It's just a hare-brained theory of mine.hare-brained scheme• This Government's many imaginative and effective initiatives are far more helpful to the regions than any hare-brained scheme from Labour. 