Volition (noun)

1. The act or power of making a choice or decision; the act of willing.
2. The faculty or power of making a choice or decisions; the ability to exercise one's own will.

Origin:

From the latin word "volitio" meaning "will".

Examples:

1. He acted on his own volition.
2. She changed her mind through an act of volition.
3. The decision was made by an act of volition.
4. She struggled with her own volition.
5. He acted with complete volition.