1. reckless or dangerously bold behavior; lack of proper caution or judgment
Usage: uncountable noun; formal register

Examples

• His foolhardiness in attempting to cross the frozen lake without proper equipment nearly cost him his life.
• The general's foolhardiness led to a devastating military defeat.
• It would be foolhardiness to drive at such high speeds in this storm.
• She criticized the company's foolhardiness in ignoring safety regulations.
• The climber's foolhardiness was evident when he scaled the mountain without a rope.
• Foolhardiness and bravery are often confused, but one involves poor judgment while the other does not.