a gut wrenching emotion felt deep in the belly of a person unrealistically looking forward to an upcoming event immediately after the reality of extreme disapointment has replaced the anticipated happiness
Heather felt nothing but anticipointment after she was told that "her" scholarship was awarded to some nerd who never takes his nose out a text book.
Most of the definitions here are simply defining "disappointment". Anticipointment is trickier than that: it's anticipating something (usually eagerly) that you expect to be disappointed by on some level as well. It's not simply anticipation followed by disappointment; it's kinda both at the same time.
The classic example is the computer-user who eagerly anticipates a price-drop on new components, but knows that the price drops because of even newer technology - which they can't afford. The user is trapped in a continuing state of anticipointment.