"Forgetting is failing to retain or to be able to recall what has been acquired."
"Forgetting means failure at anytime to recall an experience, when attempting to do so or to perform an action previously learned."
"Forgetting is a tendency toward off from memory that which is unpleasant."
None of the above.
Freud believes, there are times when an event or an action is so painful that we cannot deal with the memory of it, so we repress the memory completely. By pushing the memory into subconscious and actively repressing it, we are unable to recall the memory or called forgetting.