ETYM Old Eng. folie, foli, French folie, from fol, fou, foolish, mad. Related to Fool.
1. Foolish or senseless behavior; SYN. foolery, tomfoolery, indulgence.
2. The quality of being rash and foolish; SYN. foolishness, craziness.
3. The trait of acting stupidly or rashly; SYN. foolishness, unwiseness.
ETYM From Mad.
1. The condition of being mad; insanity; lunacy.
2. Frenzy; ungovernable rage; extreme folly. SYN. Insanity; distraction; derangement; craziness; lunacy; mania; frenzy.
State of having a disordered mind; extreme folly or infatuation. Its synonym insanity is no longer used to mean psychosis but is used primarily in medical and legal contexts to refer to mental disorders in which patients cannot be held responsible for their actions.