folly

Foolishness that results from a lack of foresight or lack of practicality.

It would be folly to walk all that way, knowing the shops are probably shut by now.

With the voices singing in our ears, saying That this was all folly.

Thoughtless action resulting in tragic consequence.

The purchase of Alaska from Russia was termed Seward's folly.

Thames Water has become the latest object lesson in the predictable and predicted folly of privatised monopolies, aided by a regulator that’s an even bigger wet wipe than the fatbergs bunging up the sewers.

A fanciful building built for purely ornamental reasons.

A luncheonette in the shape of a coffee cup is particularly conspicuous, as is intended of an architectural duck or folly.

“The Villa Straylight,” said a jeweled thing on the pedestal, in a voice like music, “is a body grown in upon itself, a Gothic folly. […]”

To follow.

"You got any money?" he said to me. ¶ "Hell no, maybe enough for a pint of whisky till I get to Denver. What about you?" ¶ "I know where I can get some." ¶ "Where?" "Anywhere. You can always folly a man down an alley, can't you?"

"Anybody got the makin's?" he said. "That's one hell of a thick bunch of canvas, but I follied the seam."

A clump of trees, particularly one on the crest of a hill (or sometimes on a stretch of open ground).

'Every hill seems to have a Folly' [...] 'I mean a clump of trees on the top.'

Folly Beach, the next island to the south (batik 3.7), bears the name given it by mariners, who looked for the island's tree-crested dune ridge, a volley or folly of trees, as a navigation guide [...] Probably a lot of East Coast islands bore the temporary name of Folly Beach.