To Augment something is to make it more bigger or more intense in some way.
Feedback is information coming to you, (i.e. fed back) usually in response to something you do.
Augmented feedback is a set of information that has been made into a bigger, or more intense experience from an action you take- sometimes artifically by an added 'thing.' One basic example is using binoculars: lifting them to your eyes, (the action you take), allows what you see (the visual input) to be exaggerated, or made to appear bigger of feel closer to you than in reality*.
Another example is by removing other inputs that are competing for your attention*. If you take a phone call in a loud restatruant, you often plug the other ear, drop your head and shouders and/or close you eyes to 'block out or occlude' those other streams of information so you can 'hear better'.
Visual Occlusion and Exaggertation are techinques used in Kinethetic Awareness Training.
*Note: attention and reality are two other HUGE subjects. More on those later.