Foolishness that results from a lack of foresight or lack of practicality. / Thoughtless action resulting in tragic consequence. / (architecture) A fanciful building built for purely ornamental reasons.

(numismatics) A large bronze coin minted during the Roman Empire.

plural of folly / (uncountable) A lavishly-produced theatrical revue characterized by major stars, huge casts, and opulent costumes and scenery.

(obsolete) Full of folly; foolish.

An unofficial nickname for the state of Alaska in the United States of America.

A tower built as an architectural folly, i.e. for ornamental rather than practical reasons.

plural of folly tower

Foolish people repeatedly do foolish things.