impetuous

characterized by undue haste and lack of thought or deliberation; ; ; ; ; (`brainish' is archaic)

Rushing with force and violence; moving with impetus; furious; forcible; violent; as, an impetuous wind; an impetuous torrent.

Latin impetus, meaning 'impulse'

“No necessity exists for any hurry, except in the brain of that impetuous boy.”

— George Meredith, Complete Project Gutenberg Works of George Meredith

“However, impetuous theatre director Aurélien-Marie Lugné-Poe took the risk, producing the play at his Théâtre de l'Œuvre.”