spontaneously

UK: /spɒnˈteɪniəsli/

WordReference Random House Learner's Dictionary of American English © 2026

spon•ta•ne•ous /spɑnˈteɪniəs/   adj. 

1. resulting from a natural impulse or tendency:
   spontaneous applause during the performance.
2. (of a person) acting upon sudden impulses:
   She's very spontaneous: she'll come right up and give you a hug if she feels like it.
3. (of natural events) caused by forces within something:
   Spontaneous combustion was the cause of the fire.

spon•ta•ne•i•ty /ˌspɑntəˈniɪti, -ˈneɪ-/  n. [uncountable]
spon•ta•ne•ous•ly, adv. 

WordReference Random House Unabridged Dictionary of American English © 2026

spon•ta•ne•ous  (spon tā′nē əs), adj. 

1. coming or resulting from a natural impulse or tendency;
   without effort or premeditation;
   natural and unconstrained;
   unplanned:
   a spontaneous burst of applause.
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. Botany growing naturally or without cultivation, as plants and fruits;
   indigenous.
5. produced by natural process.

• Late Latin spontāneus, equivalent. to Latin spont(e) willingly + -āneus (-ān(us) -an + -eus -eous)
• 1650–60

spon•ta′ne•ous•ly, adv. 
spon•ta′ne•ous•ness, n. 
Synonyms

• 1. unpremeditated, free. See automatic, voluntary. 

Antonyms

• 1. premeditated.