impulsive (suomeksi)

impulsiivinen (a: having the power of driving or impelling; giving an impulse; moving; impellent / actuated by impulse or by transient feelings / highly reactive; inclined to make rapid decisions without due consideration)
äkillinen (a: (mechanics) acting momentarily, or by impulse; not continuous)
äkkipikainen (a: highly reactive; inclined to make rapid decisions without due consideration)