Am găsit 3 definiții pentru Spontaneous:

Spontaneous - a. Proceding from natural feeling, temperament, or disposition, or from a native internal proneness, readiness, or tendency, without constraint; as, a spontaneous gift or proportion.

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

Spontaneous - a. Produced without being planted, or without human labor; as, a spontaneous growth of wood.