| 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. | Physiology. a progressive wave of excitation over a nerve or muscle fiber, having either a stimulating or inhibitory effect. |
| 8. | Mechanics. 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. | Electricity. a single, usually sudden, flow of current in one direction. |
| 10. | marked by or acting on impulse: an impulse buyer. |
| 11. | bought or acquired on impulse: To reduce expenses, shun impulse items when shopping. |

impulse im·pulse (ĭm'pŭls')
n.
A sudden pushing or driving force.
A sudden wish or urge that prompts an unpremeditated act or feeling; an abrupt inclination.
The electrochemical transmission of a signal along a nerve fiber that produces an excitatory or inhibitory response at a target tissue.