impulsive

Having the power of driving or impelling; giving an impulse; moving; impellent.

Actuated by impulse or by transient feelings; inclined to make rapid decisions without due consideration.

mechanicsActing momentarily, or by impulse; not continuous – said of forces.

Proceeding from natural feeling or impulse without external stimulus

“an impulsive gesture of affection”

Determined by chance or impulse or whim rather than by necessity or reason

“a capricious refusal”

“authoritarian rulers are frequently capricious”

“the victim of whimsical persecutions”

Characterized by undue haste and lack of thought or deliberation

“a hotheaded decision”

“liable to such impulsive acts as hugging strangers”

“an impetuous display of spending and gambling”

That which impels or gives an impulse; an impelling agent.

One whose behaviour or personality is characterized by being impulsive.