hare-brained plan

Translations
безумный план
He proposed a hare-brained plan to build a roller coaster in the backyard.
Он предложил безумный план построить американские горки во дворе.
Definitions
A hare-brained plan refers to a scheme or idea that is foolish, impractical, or lacking in common sense.
Words
harebrained

adjective
безрассудный
plan

noun
план