Impetuous

adjective/im-pet-yoo-uhs/

Meaning

acting or done quickly and without thought or care.

In context
His impetuous decision led to unforeseen consequences.

Remember it

Impetuous shares its start with 'impulse' — rushing into action before stopping to think.

Use it well

Use for hasty decisions and people: an impetuous decision, an impetuous child; formal in tone.