The meaning of FOLLY is lack of good sense or normal prudence and foresight. How to use folly in a sentence.

In architecture, a folly is a building constructed primarily for decoration, but suggesting through its appearance some other purpose, or of such extravagant appearance that it transcends the …

She said that the idea was folly. [ + to infinitive ] It would be folly for the country to become involved in the war.

Definition of folly noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

folly (ˈfɒlɪ) n, pl -lies 1. the state or quality of being foolish; stupidity; rashness 2. a foolish action, mistake, idea, etc