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lapse of memory; (something) slipping one's mind; forgetting for a moment something one knows well
大事な約束を度忘れしてしまった。
I completely forgot about an important appointment.
彼女の名前を度忘れして恥ずかしかった。
I was embarrassed to have forgotten her name.
会議の時間を度忘れして遅刻した。
I forgot the meeting time and was late.