Spontaneous :: Spontaneity (n.) The tendency to activity of muscular tissue, including the voluntary muscles, when in a state of healthful vigor and refreshment..
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 :: Spontaneous (a.) Proceeding from, or acting by, internal impulse, energy, or natural law, without external force; as, spontaneous motion; spontaneous growth..