spontaneous

Etymology

Learned borrowing from Late Latin spontāneus.

adj

1. Self-generated; happening without any apparent external cause.
   He made a spontaneous offer of help.
   a make spontaneous decision
2. Done by one's own free choice, or without planning.
3. Proceeding from natural feeling or native tendency without external or conscious constraint.
4. Arising from a momentary impulse.
5. Controlled and directed internally; self-active; spontaneous movement characteristic of living things.
6. Produced without being planted or without human cultivation or labor.
7. Random.
8. Sudden, without warning.