As a adjective foolish
is lacking good sense or judgement; unwise.
As a noun bozo is
(slang) a stupid or foolish person.
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 .
(slang) A stupid or foolish person.
* bozo eruption
Online Etymology Dictionary entry on "bozo"