Spontaneous

impulsiivinen

(arising from a momentary impulse)

luonnollinen

(produced without being planted or without human labor)

oma-aloitteinen

(done by one's own free choice, or without planning)

omaehtoinen

(done by one's own free choice, or without planning)

spontaani

(self generated; happening without any apparent external cause)

spontaani

(done by one's own free choice, or without planning)

spontaani

(not apparently contrived or manipulated)

yllättävä

(sudden, without warning)

äkillinen

(sudden, without warning)