来自拉丁语 spontaneus,自由意志的，自发的，来自短语 sua sponte,自我意志，自愿，来自 sua,
英文词源
spontaneous (adj.)
1650s, "occurring without external stimulus," from Late Latin spontaneus "willing, of one's free will," from Latin (sua) sponte "of one's own accord, willingly;" of uncertain origin. Related: Spontaneously; spontaneousness. Used earlier of persons and characters, with a sense "acting of one's own accord" (c. 1200). Spontaneous combustion first attested 1795. Spontaneous generation (the phrase, not the feat) attested from 1650s.
实用例句
1. I had another spontaneous miscarriage at around the 16th to 18th week.
我在大约第16至18孕周时又经历了一次自然流产。
来自柯林斯例句
2. spontaneous outpourings of praise
一片自然迸发的赞美声
来自《权威词典》
3. a spontaneous offer of help
主动提出帮助
来自《权威词典》
4. Spontaneous applause broke out as soon as she finished speaking.