1) The doctrine or practice of vigorous action or involvement as a
means of achieving political or other goals, sometimes by
demonstrations, protests, etc. (Dictionary.com). See also
2) Philosophy: a) A theory that the essence of reality is pure
activity, especially spiritual activity, or process.
b) A theory that the relationship between the mind and the objects of perception
depends upon the action of the mind (Dictionary.com).
→ active; → action;