Foolishness is nonsense or stupidity; it's acting in a way that is silly or irrational. Throwing a temper tantrum because the lunch line is moving slowly is pure foolishness — your outburst won't make the line move any faster.

When your actions show a lack of good sense or solid judgement, you're betraying your foolishness. Impulsively jumping off the garage roof into a pile of leaves is evidence of your foolishness. We can trace this word's origin back to fool and the Old French fol, "idiot," and also "blacksmith's bellows," from a root meaning "blow or swell."

Definitions of foolishness

n the quality of being rash and foolish

“adjusting to an insane society is total foolishness
craziness, folly, madness
Type of:
a poor ability to understand or to profit from experience

n the trait of acting stupidly or rashly

folly, unwiseness
wisdom, wiseness
the trait of utilizing knowledge and experience with common sense and insight
indiscretion, injudiciousness
the trait of being injudicious
absurdity, fatuity, fatuousness, silliness
a ludicrous folly
the quality of being asinine; stupidity combined with stubbornness
Type of:
a distinguishing feature of your personal nature

n a stupid mistake

betise, folly, imbecility, stupidity
Type of:
error, fault, mistake
a wrong action attributable to bad judgment or ignorance or inattention

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