DictionaryloonyCrazy or foolish
adjective / noun

loony

LOO-nee/ˈluːni/

Crazy or foolish, or a person regarded that way.

His loony plan covers the bicycle with tiny cocktail umbrellas.

An adult attempts an extremely impractical plan to keep rain away by attaching many tiny cocktail umbrellas to a bicycle, looking absurdly confident.
Etymology

Loony shortens lunatic, which originally described insanity believed to vary with the moon. The shortened adjective broadened into an informal description of someone or something crazy, silly, or eccentric.

In context

Old Time Radio Researchers11:28
there's a loony old coot named a pac-mule parker yeah we ran into him he's got the mistaken idea that he owns practically all the mining country around here and has to protect it against trespassers
Hopalong Cassidy - The Secret in the Hill

More examples

  • She called the proposal loony.
  • He regretted calling the protesters loonies.
  • The idea sounded loonier every minute.

Forms

loony · loonies · loonier · looniest

Similar words

foolish
A less insulting description of poor judgment.
absurd
Emphasizes lack of sense rather than presumed mental state.