The quality of being forgetful; prononess to let slip from the mind.
Loss of remembrance or recollection; a ceasing to remember; oblivion.
Failure to bear in mind; careless omission; inattention; as, forgetfulness of duty.
unawareness caused by neglectful or heedless failure to remember; "his forgetfulness increased as he grew older"
state of neglectful or heedless failure to remember ( Mental Clarity)