1. (a.) Impulsive; extemporaneous; proceeding from natural feeling\, temperament, or disposition, or from a native internal proneness, readiness, or tendency, without constraint; as, a spontaneous gift or proportion.

2. (a.) Proceeding from, or acting by, internal impulse, energy, or natural law, without external force; as, spontaneous motion; spontaneous growth.

3. (a.) Produced without being planted, or without human labor; as, a spontaneous growth of wood.

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