Spontaneous

a.	1.	Proceeding from natural feeling, temperament, or disposition, or from a native internal proneness, readiness, or tendency, without constraint; as, a spontaneous gift or proposition.
	2.	Proceeding from, or acting by, internal impulse, energy, or natural law, without external force; as, spontaneous motion; spontaneous growth.
	3.	Produced without being planted, or without human labor; as, a spontaneous growth of wood. Spontaneous combustion combustion produced in a substance by the evolution of heat through the chemical action of its own elements; as, the spontaneous combustion of waste matter saturated with oil. Spontaneous generation (Biol.) See under Generation. Spontaneous joys, where nature has its play, The soul adopts, and owns their firstborn away. - Goldsmith.

Adj.	1.	spontaneous - happening or arising without apparent external cause; "spontaneous laughter"; "spontaneous combustion"; "a spontaneous abortion" Synonyms: self-generated Antonyms: induced - brought about or caused; not spontaneous; "a case of steroid-induced weakness"
	2.	spontaneous - said or done without having been planned or written in advance; "he made a few ad-lib remarks" Synonyms: ad-lib, unwritten
	3.	spontaneous - produced without being planted or without human labor; "wild strawberries" Synonyms: wild

ad lib, arbitrary, automated, automatous, autonomous, bat, baton, billy, billy club, bludgeon, casual, club, cybernated, discretional, discretionary, elective, extempore, free, free will, gratuitous, gut, ill-advised, ill-considered, ill-devised, immediate, impetuous, impromptu, improvised, inadvertent, indeliberate, independent, inherent, innate, instinctual, involuntary, libidinal, mace, mechanical, nightstick, nonmandatory, off the cuff, offered, offhand, optional, proffered, reflex, reflexive, self-acting, self-active, self-adjusting, self-closing, self-controlled, self-cooking, self-determined, self-determining, self-directed, self-directing, self-dumping, self-governed, self-governing, self-lighting, self-operative, self-regulative, self-starting, self-winding, self-working, semiautomatic, simple, snap, spontoon, spur-of-the-moment, subliminal, truncheon, unadvised, unannounced, unasked, unbesought, unbidden, uncalculated, uncalled-for, uncoerced, uncompelled, unconscious, unconsidered, unconstrained, undeliberate, undeliberated, undesigned, unforced, unguarded, uninfluenced, unintended, unintentional, uninvited, unlearned, unmeditated, unplanned, unpremeditated, unprepared, unpressured, unprompted, unrehearsed, unrequested, unrequired, unsolicited, unsophisticated, unsought, unstudied, unthinking, unwilled, unwitting, volunteer, willful