foolish
adj. B1 Intermediate US //ˈfuɫɪʃ// UK //fˈuːlɪʃ// fool·ish
adj. acting in a way that is not wise or shows a lack of good judgment. You use this to describe someone who makes a silly mistake that could have been avoided.
adj. lacking good sense or judgement; unwise. Often used to describe specific actions or decisions rather than an inherent character trait.
It was foolish to leave the car unlocked in the city.
Investing all of your savings into a single unproven company is a foolish financial move.
The explorer realized too late that his foolish disregard for the local weather patterns would likely jeopardize the entire mission's success.
From Middle English folisch; equivalent to fool + -ish.
Usage
Typically used as an attributive adjective before a noun or as a predicative adjective after a linking verb.