Impulsive

a. [It. & Sp. impulsivo, Pr. impulsíu, Fr. impulsif.] 1. Having the power of driving or impelling; moving; impellent. Poor men! poor papers! We and they Do some impulsive force obey. Prior.

2. Actuated by impulse; as, a person who is impulsive often acts unwisely.
3. (Mech.) Acting momentarily, or by impulse; not continuous; — said of forces.