proceeding from innate tendency, natural feeling or sudden impulse innate tendency without external constraint
a spontaneous expression of gratitude
by nature unconstrained or uninhibited
springing from a sudden impulse
a spontaneous offer of help
controlled and directed internally
developing without apparent external influence or, force, cause, or treatment
spontaneous recovery
archaic said of plants: indigenous; natural
spontaneity /spontəʹnayiti, -ʹneeiti/ noun
spontaneously adv
spontaneousness noun
[late Latin spontaneus from Latin sponte of one's free will, voluntarily]