Meaning of “spontaneous” - Learner’s Dictionary

spontaneous

adjective uk us /spɒnˈteɪniəs/

happening naturally and suddenly and without being planned:

a spontaneous reaction
The crowd broke into spontaneous applause.
spontaneity uk us /ˌspɒntəˈneɪəti/ noun [ U ]

the quality of being spontaneous:

The performance was boring and lacked spontaneity.
spontaneously adverb

(Definition of “spontaneous” from the Cambridge Learner’s Dictionary © Cambridge University Press)