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1. The trait of acting stupidly or rashly
   - foolishness, unwiseness
    
2. A stupid mistake
   - stupidity, bêtise, foolishness, imbecility
    
3. The quality of being rash and foolish
   "trying to drive through a blizzard is the height of folly"
   - foolishness, craziness, madness, nuttiness
    
4. Foolish or senseless behaviour
   - foolery, tomfoolery, craziness, lunacy, indulgence

Derived forms: follies

Type of: caper, error, fault, frolic, gambol, mistake, play, romp, stupidity, trait

Antonym: wisdom

Encyclopedia: Folly