What does impulse mean?
An impulse is a sudden urge to act, think, or do something, often before there has been time for reflection. Expressions such as “on impulse” and “impulse purchase” describe decisions made spontaneously rather than through deliberate planning. The word can also describe the motivation behind an action, as in “an impulse to explore.” In physics, an impulse is the effect of a force acting over time and is responsible for a change in an object’s momentum. In biology, a nerve impulse is an electrical signal transmitted along a nerve. The verb “impulse” means to drive someone to act hastily or spontaneously. Because it combines a clear everyday sense with specialized scientific meanings, the word is useful when discussing both human behavior and measurable physical processes.
A sudden, strong urge to do something, often without careful thought; an impetus to act; or, in physics, a force acting over time that changes momentum.
"She reached for the phone on impulse."
The everyday sense commonly implies spontaneity, while the physics sense is a technical term for the time integral of force.
To drive someone to act suddenly or without careful thought; to impel.
"The advertisement impulsed customers to buy the product immediately."
This is a formal or literary verb and is less common in everyday speech than the noun.
The plural is used for separate urges or impulses and for individual instances of a physical impulse.
"The experiment recorded the impulses sent through the nerve."
An impulse can arrive in a fraction of a second and, in physics, can also change an object's momentum.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does impulse come from?
The word comes from Latin impulsus, the past participle of impellere, meaning “to drive forward” or “to push.” English borrowed the noun in the sense of an impulse or impetus, and the verb developed from the idea of driving or impelling someone to act. The same Latin root appears in impulsive, impulsion, and impulsiveness, as well as in the related Latin-derived verb impel.
Related word forms
How impulse is actually used
The noun is common in both formal and informal English. In everyday use, it usually suggests acting before reflection; in scientific contexts, it has a precise technical meaning. The verb is usually transitive and means to cause someone to act suddenly or without careful thought.
Easily confused with impulse
An impulse is the urge itself, whereas impulsive describes a person or action characterized by acting on such urges.