a. rash; marked by unthinking boldness
Don't be foolhardy. Get the advice of experienced people before undertaking this venture.
Sentence in Classic:
Now, to engage in a combat wherein you risk your whole fortunes without putting forth your entire strength, is, as I observed before, when condemning the defence of a country by guarding its defiles, an utterly foolhardy course.
Discourses on the First Decade of Titus Livius By Niccolo Machiavelli Context
The foolhardiness or ignorance of her officers was a prolific theme for comment whilst she remained in sight, and efforts were made to signal her to reduce sail in face of her danger.