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Synonyms

spontaneous

American  
[spon-tey-nee-uhs] / spɒnˈteɪ ni əs /

adjective

  1. coming or resulting from a natural impulse or tendency; without effort or premeditation; natural and unconstrained; unplanned.

    a spontaneous burst of applause.

    Synonyms:
    free, unpremeditated
    Antonyms:
    premeditated
  2. (of a person) given to acting upon sudden impulses.

  3. (of natural phenomena) arising from internal forces or causes; independent of external agencies; self-acting.

  4. growing naturally or without cultivation, as plants and fruits; indigenous.

  5. produced by natural process.


spontaneous British  
/ spɒnˈteɪnɪəs /

adjective

  1. occurring, produced, or performed through natural processes without external influence

    spontaneous movement

  2. arising from an unforced personal impulse; voluntary; unpremeditated

    a spontaneous comment

  3. (of plants) growing naturally; indigenous

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Usage

What does spontaneous mean? Spontaneous means natural and unplanned. When you describe an action or event as spontaneous, it means it happened naturally, without having been planned, as in The meeting turned into a spontaneous dance party. When something that someone does is described as spontaneous, it means it was done out of a natural impulse, without having been thought about beforehandWhen spontaneous is used to describe a person, it means they have a tendency to or are known for doing things impulsively and without planning. This is usually used in a positive way to portray them as a fun person who is adventurous and willing to do things on the spur of the moment. Telling someone to be more spontaneous means you want them to be more flexible and willing to do more things on a whim instead of needings for things to be completely structured or scheduled. The state or quality of being spontaneous is spontaneity. In a scientific context, spontaneous is used to describe effects that happen independently, without being acted on by outside forces. The most well-known example of its use in this sense is in the term spontaneous combustion, in which something catches on fire due to an internal chemical reaction (as opposed to external ignition). Example: Julian’s friends knew him as a spontaneous guy who was always up for going on random adventures.

Synonym Usage

See automatic, voluntary.

Other Word Forms

Etymology

Origin of spontaneous

First recorded in 1650–60; from Late Latin spontāneus, equivalent to Latin spont(e) “willingly” + -āneus ( -ān(us) -an + -eus -eous )

Explanation

Something spontaneous happens when you're least expecting it. Spontaneous things are natural or instinctive, and they happen without warning. If you plan to go to a movie and then you go, that's not a spontaneous thing. Ditching the movie at the last minute to go to the park? That's spontaneous. Spontaneous things happen all of a sudden, on the spur of the moment, without being planned. Spontaneous can also refer to things that happen without outside influence. Your parents will be happy if you do your chores spontaneously instead of waiting till they nag you.

Keep Reading on Vocabulary.com

Vocabulary lists containing spontaneous

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.

Base told Rolling Stone in a 2014 interview the song's creation was spontaneous and he was shocked by its success.

From BBC • May 23, 2026

Most cancers are spontaneous and can’t be detected in a genetic test.

From Barron's • May 21, 2026

“She had a spontaneous unexplained brain bleed that led to brain death.”

From Salon • May 7, 2026

And what better indication of the demise of the spontaneous phone call can be found?

From The Wall Street Journal • May 1, 2026

Citra knew it would be healed by morning, but the healing nanites were not spontaneous.

From "Scythe" by Neal Shusterman

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