IPA: /spɒnˈteɪ.nəs/
KK: /spɑnˈteɪ.nəs/
Occurring naturally without being planned or forced; happening on its own.
The spontaneous laughter of the children filled the room with joy.
Spontaneous → It is formed from "sponte" (meaning of one's own accord) and the suffix "-ous" (meaning full of). The word "spontaneous" describes actions that occur naturally or of one's own will, without external influence.
Think of actions that happen 'of one's own accord' — that's what spontaneous means, as it reflects doing something naturally and without prompting.