Definitions

spontaneous

[spon-tey-nee-uhs] / spɒnˈteɪ ni əs /

ADJECTIVE

impulsive, willing

Synonyms

STRONGEST

casual impromptu instinctive offhand simple unplanned voluntary

WEAK

ad-lib automatic break loose down extemporaneous extempore free free-spirited from the hip impetuous improvised inevitable involuntary irresistible natural off top of head off-the-cuff unartful unavoidable unbidden uncompelled unconscious unconstrained uncontrived uncontrolled unforced unintentional unpremediated unprompted unsophisticated unstudied up front

Antonyms

STRONGEST

deliberate planned

WEAK

intended premeditated

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Rather than reinventing himself, Raina seems to be adjusting his approach - testing how far his loose, spontaneous style can go without breaking.

From BBC • Apr. 10, 2026

They quickly return to a lower energy state by releasing light at a specific frequency, a process known as spontaneous emission.

From Science Daily • Apr. 10, 2026

This one-sided empathy is not a spontaneous response to compelling facts, however.

From Slate • Apr. 3, 2026

Vance, though, is clearly incapable of such a spontaneous response.

From Salon • Apr. 1, 2026

The cheerleaders erupted into a spontaneous little cheer of “Midland High, yeah, Midland High!” and then Air Force II came into view.

From "Friday Night Lights: A Town, A Team, And A Dream" by H.G. Bissinger

Vocabulary lists containing spontaneous

Essential Academic Vocabulary for High School Students, List 1

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100 Top "SAT" Words

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Animal Farm

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