Pronunciation: (im'puls), [key]
1. the influence of a particular feeling, mental state, etc.: to act under a generous impulse; to strike out at someone from an angry impulse.
2. sudden, involuntary inclination prompting to action: to be swayed by impulse.
3. an instance of this.
4. a psychic drive or instinctual urge.
5. an impelling action or force, driving onward or inducing motion.
6. the effect of an impelling force; motion induced; impetus given.
7. Physiol.a progressive wave of excitation over a nerve or muscle fiber, having either a stimulating or inhibitory effect.
8. Mech.the product of the average force acting upon a body and the time during which it acts, equivalent to the change in the momentum of the body produced by such a force.
9. Elect.a single, usually sudden, flow of current in one direction.
1. marked by or acting on impulse: an impulse buyer.
2. bought or acquired on impulse: To reduce expenses, shun impulse items when shopping.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.