Foolishness is a derived term of foolish.
As a adjective foolish
is lacking good sense or judgement; unwise.
As a noun foolishness is
(uncountable) the state of being foolish.
Other Comparisons: What's the difference?
Lacking good sense or judgement; unwise.
*:As a political system democracy seems to me extraordinarily foolish , but I would not go out of my way to protest against it. My servant is, so far as I am concerned, welcome to as many votes as he can get. I would very gladly make mine over to him if I could.
Resembling or characteristic of a fool.
*:It is a profitable thing, if one is wise, to seem foolish .
(uncountable) The state of being foolish.
(countable) A thing or event that is foolish, or an absurdity.
* imprudence, folly
* extravagance, irresponsibility
* indiscretion, absurdity