Definition of "impulsive"

impulsive

/ɪmˈpʌlsɪv/

adjective
comparative more impulsive, superlative most impulsive
1. Having the power of driving or impelling; giving an impulse; moving; impellent.
  Quotations
  Poor men! poor papers! We and they / Do some impulsive force obey.
  1718, Mat[thew] Prior, “Alma: Or, The Progress of the Mind”, in Poems on Several Occasions, London: […] Jacob Tonson […], and John Barber […]
2. Actuated by impulse or by transient feelings; inclined to make rapid decisions without due consideration.
  Quotations
  my heart, impulsive and wayward
  1847 November 1, Henry Wadsworth Longfellow, Evangeline, a Tale of Acadie, Boston, Mass.: William D. Ticknor & Company, (please specify either |part=I or II)
3. (mechanics) Acting momentarily, or by impulse; not continuous – said of forces.
noun
plural impulsives
1. That which impels or gives an impulse; an impelling agent.
  Quotations
  Notwithstanding all which Motives and impulsives , Sir Thomas Overbury refused to be sent abroad , with such terms
  1613, Henry Wotton, letter to Edmund Bacon
2. One whose behaviour or personality is characterized by being impulsive.