Folly

Fol"ly (?), n.; pl. Follies (#). [OE. folie, foli, F. folie, fr. fol, fou, foolish, mad. See Fool.] 1. The state of being foolish; want of good sense; levity, weakness, or derangement of mind.

2. A foolish act; an inconsiderate or thoughtless procedure; weak or light-minded conduct; foolery.

What folly 'tis to hazard life for ill.
Shak.

3. Scandalous crime; sin; specifically, as applied to a woman, wantonness.

[Achan] wrought folly in Israel.
Josh. vii. 15.

When lovely woman stoops to folly.
Goldsmith.

4. The result of a foolish action or enterprise.

It is called this man's or that man's "folly," and name of the foolish builder is thus kept alive for long after years.
Trench.