Definition

1. Noun:
   • A sudden strong and unreflective urge or desire to act: A spontaneous, often momentary, drive to do something without careful thought.
   • A driving or motivating force; an impetus: Something that causes motion or action, either physical or psychological.
   • (Physics) The product of the average force acting on a body and the time during which it acts, producing a change in momentum: A measure of the effect of a force applied over time.
   • (Physiology) A signal transmitted along a nerve fiber: The electrochemical wave that carries information through the nervous system.
   • (Electronics) A brief, sudden change in a voltage or current; a pulse: A short-duration surge in an electrical signal.

Examples of Usage

• Noun:
  • She felt a sudden impulse to call her old friend. (Describes a spontaneous urge.)
  • The discovery gave a fresh impulse to the research. (Describes a motivating force.)
  • The impulse of the collision sent the car spinning. (Describes a physical driving force.)
  • A nerve impulse travels from the brain to the muscles. (Describes a physiological signal.)
  • The circuit is triggered by an electrical impulse. (Describes an electronic signal.)

Advanced Usage

• "On impulse": Acting spontaneously, without prior planning.
  • He bought the expensive watch on impulse.
• "Impulse buy/purchase": An unplanned purchase made on a whim.
  • The candy at the checkout is designed to encourage impulse buys.
• "To resist/control an impulse": To stop oneself from acting on a sudden urge.
  • She had to resist the impulse to interrupt.

Variants and Related Words

• Impulsive (adj): Acting or done without forethought; prone to acting on impulse.
  • He is known for his impulsive decisions.
• Impulsively (adv): In an impulsive manner.
  • She acted impulsively.
• Impulsiveness (n): The quality of being impulsive.
  • His impulsiveness often gets him into trouble.

Synonyms

• Urge: A strong desire or impulse.
• Whim: A sudden desire or change of mind.
• Impetus: The force or energy with which a body moves; a driving force.
• Spur: A thing that prompts or encourages someone; an incentive.

Related Phrases

• Impulse control: The ability to resist or delay an impulse.
  • Children learn impulse control as they grow.
• Impulse response: (In engineering/signal processing) The output of a system when presented with a brief input signal (an impulse).
  • Analyzing the impulse response helps understand the system's behavior.

Related Idioms

• A rush of blood to the head: (Informal) A sudden impulsive feeling that makes someone act foolishly. (Similar in meaning to acting on a reckless impulse.)
  • It was just a rush of blood to the head that made him say that.

Noun

1. an impelling force or strength
   • the car's momentum carried it off the road
2. the act of applying force suddenly
   • the impulse knocked him over
3. (electronics) a sharp transient wave in the normal electrical state (or a series of such transients)
   • the pulsations seemed to be coming from a star
4. the electrical discharge that travels along a nerve fiber
   • they demonstrated the transmission of impulses from the cortex to the hypothalamus
5. a sudden desire
   • he bought it on an impulse
6. an instinctive motive
   • profound religious impulses