dy•nam•ic

adjective
     1. Characterized by continuous change, activity, or progress: a dynamic      market.
     2. Positive in attitude and full of energy and new ideas: a dynamic person.
     3. Expressing an action, activity, event, or process: dynamic content.
     4. Of or relating to energy or to objects in motion: a dynamic movement.

noun
     1. A force that stimulates change or progress within a system or process: the      dynamic of a project.