What's the difference between forgetfulness and irretention?

Forgetfulness

Definition:

(n.) The quality of being forgetful; prononess to let slip from the mind.
(n.) Loss of remembrance or recollection; a ceasing to remember; oblivion.
(n.) Failure to bear in mind; careless omission; inattention; as, forgetfulness of duty.

Example Sentences:

(1) One of the most interesting aspects of the shadow cabinet elections, not always readily interpreted because of the bizarre process of alliances of convenience, is whether his colleagues are ready to forgive and forget his long years as Brown's representative on earth.
(2) When tested 4 weeks later, they showed significant forgetting.
(3) They make a big deal when it happens, and then they forget.” The use of sarin has been highly contentious throughout the Syrian war.
(4) All freedom-loving people will miss him, but we will never forget his sacrifice and his achievements."
(5) But we shouldn’t forget that Gawker was not just getting sued over the Hulk Hogan sex tape case.
(6) Oh, and let’s not forget about him doing bad dance moves in a video making fun of Drake’s choreography in the Hotline Bling video.
(7) "We have vowed to never forget and we never will," he said.
(8) Seethetree Kingley Vale, Sussex Forget the colours of autumn; this place is sombre in colour and atmosphere but you will be walking among probably the oldest living organisms in Britain.
(9) You will also need to find alternative disposable bags for shops to stock while people get into the habit of bringing their own bag, however, and for when they forget.
(10) Also, if you want to press vinyl, forget it – leading up to this day all of the pressing plants are booked.
(11) This was generally mild and always fully reversible and consisted mainly of forgetfulness, occasionally hallucinations, nightmares and somnolence.
(12) Results for the backward-counting condition duplicate, for the retention intervals used, the shape of the classic Peterson and Peterson forgetting curve but indicate little loss of memory in either the rehearsal or alpha conditions.
(13) Forget about the infants' milk, only lucky children can get it.
(14) Effectiveness of the neuropharmacological actions improving the memory forgotten trace retrieval is shown to depend upon the duration of the spontaneous forgetting process.
(15) The first symptom of the younger brother (case 2) was also forgetfulness at 45 years old, then severe dementia was advanced, at last he died of pneumonia at age 53 old.
(16) Our board of trustees already involves [the ice hockey player] Ilya Kovalchuk and his wife Nicole, and we are now negotiating with [the boxer] Roy Jones Jr, who recently received Russian citizenship.” It is clear that Shatov is an achiever more than than a dreamer – a down-to-earth character who will never forget where he came from.
(17) Ultimately, we are fallible and forgetful, so the best way to solve the problem is as always choice-editing or design this inconvenience out.
(18) Nor should we forget why the Conservatives were so eager to seize that chance: they saw the opportunity to wipe out the achievements of Tony Blair and Gordon Brown, who demonstrated, over many years of hard graft, that the country’s economic management was safe in Labour’s hands.
(19) Deliberate forgetting Wouldn't it be useful if our minds had their own refuse collection service – a way of selectively depositing those memories we no longer require while keeping hold of those that we do?
(20) Obama acknowledged he had read an article "in the news just the other day wondering has Washington missed its opportunity, because as time goes on after Newtown, somehow people start moving on and forgetting" This was not the case, he said.