impetus

noun

im·​pe·​tus ˈim-pə-təs 

1

a(1)

: a driving force : impulse

(2)

: incentive, stimulus

b

: stimulation or encouragement resulting in increased activity

2

: the property possessed by a moving body in virtue of its mass and its motion

—used of bodies moving suddenly or violently to indicate the origin and intensity of the motion

Did you know?

Impetus Has Latin Roots

Impetus comes from the Latin verb impetere, meaning "to attack," which is a combination of the prefix in-, meaning "toward," with petere, meaning "to go to" or "to seek." Hence, impetus describes the kind of force that encourages an action ("The impetus behind the project") or the momentum of an action already begun ("The meetings only gave impetus to the rumors of a merger").

Synonyms

• boost
• encouragement
• goad
• impulse
• incentive
• incitation
• incitement
• instigation
• momentum
• motivation
• provocation
• spur
• stimulant
• stimulus
• yeast

Examples of impetus in a Sentence

In a revealing comment, Mr. Updike says an impetus for Rabbit, Run was the "threatening" success of Jack Kerouac's On the Road, the signature book of the 1950s Beat Generation, and its frenetic search for sensation. —Dennis Farney, Wall Street Journal, 16 Sept. 1992

But 1939 gave new impetus to the Western with the Cecil B. de Mille railway epic Union Pacific, John Ford's skillful and dramatic Stagecoach,  … and George Marshall's classic comic Western, Destry Rides Again. —Ira Konigsberg, The Complete Film Dictionary, 1987

… new techniques of navigation and shipbuilding enlarged trade and the geographical horizon; newly centralized power absorbed from the declining medieval communes was at the disposal of the monarchies and the growing nationalism of the past century gave it impetus … —Barbara W. Tuchman, The March of Folly, 1984

His discoveries have given impetus to further research.

the reward money should be sufficient impetus for someone to come forward with information about the robbery

Recent Examples on the Web

The impetus for his ire had everything to do with Minnesota big man Rudy Gobert, who was being chastised by the fan when Edwards decided to step in and take over the exchange. —Sam Amick, New York Times, 29 Apr. 2025

Union leaders said the impetus for the strike was a string of 44 labor law violations allegedly committed by the county, including retaliation and contracting out work that’s supposed to be done by union members. —Rebecca Ellis, Los Angeles Times, 28 Apr. 2025

That was the impetus to provide that sort of content, to be a shorthand of what this experience could be. —Rob Wieland, Forbes.com, 22 Apr. 2025

The impetus wasn’t solely eugenic; Bell and other advocates believed that only by learning to speak could the deaf function in a world in which the vast majority of people can hear. —David Owen, New Yorker, 21 Apr. 2025

Word History

Etymology

Latin, assault, impetus, from impetere to attack, from in- + petere to go to, seek — more at feather

First Known Use

1641, in the meaning defined at sense 1a(1)

Kids Definition

impetus

noun

im·​pe·​tus ˈim-pət-əs 

1

a

: a driving force : impulse

b

: incentive

2

: momentum sense 1