spontaneous
- 1Done of one's own free choice or without planning; also, arising from a sudden, passing impulse.
Their trip to the coast was spontaneous: they packed the car an hour after the idea came up.
No one had asked him to volunteer, so his offer to stay late was entirely spontaneous.
Similarimpulsive, unplanned, impromptu, voluntary, unprompted
Oppositeplanned, premeditated
- 2Coming from natural feeling or an inborn tendency, without being held in check by outside forces or by conscious control.
Children show a spontaneous curiosity about anything that moves.
His spontaneous warmth toward strangers was something no one could fake.
Similarnatural, instinctive, unforced, genuine, uninhibited
- 3Produced from within rather than by something outside; happening without any apparent external cause.
Doctors found no injury that could account for the patient's spontaneous bleeding.
Investigators ruled the barn fire spontaneous, since the damp hay had heated up and ignited on its own.
Similarautonomous
Oppositeinduced
- 4
- 5Controlled and directed from within rather than from outside; self-acting, as is the independent movement typical of living things.
The biologists separated the animal's spontaneous movements from those triggered by touch or light.
The heart muscle cells kept up their spontaneous beating even after being removed from the body.
Similarautonomous
Oppositeinduced
- 6Growing of its own accord rather than being planted, tended, or raised by human labor, as wild fruit and self-sown plants do.
Within a few years, spontaneous vegetation had covered the abandoned rail yard.
The ecologists counted every spontaneous plant that had sprung up between the paving stones.
Similarwild
Oppositecultivated
Less common meaning
- 7Sudden, without warning.
Practice
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Origin
A learned borrowing from the Late Latin word spontāneus.