spontaneously

spontaneously — adverb

1. Done because of a sudden inner desire or natural feeling, without being arranged

1.adverbB2
Definition

Done because of a sudden inner desire or natural feeling, without being arranged, forced, or thought about beforehand.

Example

Tomás spontaneously decided to fly to Tokyo after spotting a cherry-blossom poster.

spontaneously + decide + to-infinitive

The crowd spontaneously burst into cheers when the final goal was scored.

Common collocations
  • decide spontaneously
  • act spontaneously
  • burst into (cheers/laughter) spontaneously
  • form (a group/circle) spontaneously
Synonyms
  • naturally

    broader; can describe an innate quality rather than a specific unplanned action

  • impulsively

    stronger; suggests acting without thinking at all, not just without prior planning

  • instinctively

    based on inborn instinct rather than a conscious feeling or choice

Antonyms
  • deliberately

    implies careful thought and intention, the opposite of acting on impulse

  • premeditatedly

    formal; suggests the action was planned and considered in advance

Grammar Patterns

spontaneously + verb

verb + spontaneously

Usage Note

Common with verbs of decision, reaction, or group behaviour (decide, burst, start, laugh, form). Often describes positive, unforced human actions in social or emotional settings.

Common Mistakes

The car spontaneously stopped in the middle of the road' (when you mean it stopped suddenly).
The car suddenly stopped in the middle of the road.
'spontaneously' implies an inner will or natural impulse; a machine does not act of its own accord.

2. In a way that happens by itself, without a clear or visible outside cause, trigg

2.adverbC1
Definition

In a way that happens by itself, without a clear or visible outside cause, trigger, or human effort.

Example

The rash on Maeve's arm appeared spontaneously — the doctors could not find a cause.

spontaneously + appear (medical context)

Under certain conditions, a chemical reaction begins spontaneously without any added heat.

spontaneously + begin (scientific process)

Common collocations
  • appear spontaneously
  • occur spontaneously
  • arise spontaneously
  • begin spontaneously
Synonyms
  • automatically

    suggests a mechanical or programmed process, not necessarily a natural one

  • involuntarily

    implies the action happens without or against one's will, not simply without a cause

Grammar Patterns

spontaneously + verb

verb + spontaneously

Usage Note

Frequently used in scientific, medical, and physical contexts where no external trigger is visible. Common verbs include appear, occur, arise, begin, and grow. This sense does not describe human choices or social behaviour.

Common Mistakes

He spontaneously found his keys under the sofa' (when you mean by chance).
He happened to find his keys under the sofa.
'spontaneously' describes a process coming from within, not an event caused by external chance.

Word family

Synonym discussion

Sense: adverb/1

Spontaneously, naturally, impulsively, and instinctively all describe unforced behaviour, but they differ in what drives it. Naturally is the broadest — it can describe someone's general character (She is naturally shy) rather than a single unplanned act. Impulsively is stronger and often carries a hint of recklessness or lack of self-control, as in He impulsively quit his job without a backup plan. Instinctively points to inborn animal or human reflexes rather than a conscious emotional impulse — a mother instinctively reaches for a falling child, but she might spontaneously invite a friend to dinner. Use spontaneously when the emphasis is on the absence of planning and the presence of free, genuine feeling.

naturally ↗impulsively ↗instinctively

Common collocations

Phrases

  • happen spontaneously
  • come about spontaneously

Etymology

LatinLate LatinEnglish

Spontaneously comes from the Latin adverb sponte, meaning 'of one's own free will.' In Late Latin the adjective spontaneus was formed, and English borrowed spontaneous from it in the mid-1600s, adding the suffix -ly to create the adverb. The word originally carried a strong sense of voluntary, unforced choice, which later broadened to include natural processes that seem to happen on their own.