spontaneity

n.; pl. Spontaneities [ Cf. F. spontanéité. ] 1. The quality or state of being spontaneous, or acting from native feeling, proneness, or temperament, without constraint or external force. [ 1913 Webster ]

Romney Leigh, who lives by diagrams,
And crosses not the spontaneities
Of all his individual, personal life
With formal universals. Mrs. Browning. [ 1913 Webster ]

2. (Biol.) (a) The tendency to undergo change, characteristic of both animal and vegetable organisms, and not restrained or checked by the environment. (b) The tendency to activity of muscular tissue, including the voluntary muscles, when in a state of healthful vigor and refreshment. [ 1913 Webster ]