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Showing results for spontaneous.
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.

"We got a return of spontaneous circulation," Page said.

From BBC • Apr. 6, 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

This type of spontaneous movement has been linked to longevity in other species as well.

From Science Daily • Mar. 26, 2026

From this Anaximander concluded that human beings arose from other animals with more self-reliant newborns: He proposed the spontaneous origin of life in mud, the first animals being fish covered with spines.

From "Cosmos" by Carl Sagan

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.