foolish

Etymology

From Middle English folisch; equivalent to fool + -ish.

adj

1. (of a person, an action, etc.) Lacking good sense or judgement; unwise.
   Next season will, as ever, be a different matter, another problem for Conte to solve as he looks to extend his personal record of four straight league titles in club football across England and Italy. Given his hunger for more – more time, more detail, more work – only the brave or the foolish would bet against him. May 13, 2017, Barney Ronay, “Antonio Conte’s brilliance has turned Chelsea’s pop-up team into champions”, in the Guardian
2. Resembling or characteristic of a fool.