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.

In 2024, for example, more than 700 newborns died from spontaneous bleeding in their brains, which could have been complicated by liver disease or prematurity.

From Salon • May 7, 2026

Is time for a more old school, and spontaneous, connection?

From The Wall Street Journal • May 2, 2026

Our first clue that this leave-taking lies somewhere between planned and spontaneous is in Martin’s gently charged response in answer to his daughter’s initial confusion: What would you take if the house were on fire?

From Los Angeles Times • May 1, 2026

Although they appear spontaneous, there is a level of coordination and predictability to them.

From BBC • Apr. 28, 2026

‘While you’re at it you can cross off the one about spontaneous explosion or whatever it’s called.’

From "The London Eye Mystery" by Siobhan Dowd

Vocabulary lists containing spontaneous

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