1.Definition: insanely irresponsible

"An idiotic idea"

Related Adjective(s):crackbrained

2.Definition: so unreasonable as to invite derision

Related Adjective(s):absurd, cockeyed, derisory, laughable, ludicrous, nonsensical, preposterous, ridiculous

3.Definition: very foolish or dumb

Related Adjective(s):imbecile, imbecilic