That which impels or gives an impulse; an impelling agent.
One whose behaviour or personality is characterized by being impulsive.
Acting momentarily, or by impulse; not continuous – said of forces.
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.
An operative person or thing.
Any of a class of behaviors that produce consequences by operating (i.e., acting) upon the environment.
That operates to produce an effect.