spontaneity

Short definition from Wiktionary

Noun

1. 1
   The quality of being spontaneous.
2. 2
   Spontaneous behaviour.
3. 3
   The tendency to undergo change, characteristic of both animal and vegetable organisms, and not restrained or checked by the environment.
4. 4
   The tendency to activity of muscular tissue, including the voluntary muscles, when in a state of healthful vigour and refreshment.