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 state’s budget could be the impetus for a third special session of the General Assembly in as many years — especially if federal cuts to Medicaid materialize. —Nick Coltrain, Denver Post, 9 May 2025

So strong is the impetus to continue to try to be as hot as possible, at all costs. —Mara Gordon, NPR, 8 May 2025

Another internal document, which provides extraordinary insight into the administration’s efforts to reshape the NIH, also states the executive order was the impetus for grant terminations. —Annie Waldman, ProPublica, 7 May 2025

Trump’s tariff crusade surely was another impetus for the trade trips. —Charles Selle, Chicago Tribune, 5 May 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