Authentic is, nonetheless, difficult to define. Most definitions of authentic compare one thing to some existing model or template. Something is authentic if it compares well to the original. In their paper on authentic activities and online learning Reeves, Herrington and Oliver describe what authenticity means in the design of learning activities. They present ten characteristics that define authentic Active Learning activities.
Each of these design features is described in a more detailed post. Follow the links in the list above.