- coming or resulting from a natural impulse or tendency; without effort or premeditation; natural and unconstrained; unplanned: a spontaneous burst of applause.
- (of a person) given to acting upon sudden impulses.
- (of natural phenomena) arising from internal forces or causes; independent of external agencies; self-acting.
- growing naturally or without cultivation, as plants and fruits; indigenous.
- produced by natural process.
- occurring, produced, or performed through natural processes without external influencespontaneous movement
- arising from an unforced personal impulse; voluntary; unpremeditateda spontaneous comment
- (of plants) growing naturally; indigenous
adj.1650s, from Late Latin spontaneus “willing, of one’s free will,” from Latin (sua) sponte “of one’s own accord, willingly;” of unknown origin. Related: Spontaneously. Earliest use is of persons and characters. Spontaneous combustion first attested 1795. Spontaneous generation (the phrase, not the event) attested from 1650s.