Time-fade
From Tardis Wiki, the free Doctor Who reference
Time-fade occurred when an individual was removed from time, causing the memory of them to disappear over time.
When the Sild kidnapped every incarnation of the Master, his incarnation imprisoned by UNIT began to experience time-fade, though he was unaware of it. Brigadier Lethbridge-Stewart, Jo Grant, and other UNIT staff began to forget about the Master, knowing that there was someone important but not knowing his name. (PROSE: Harvest of Time)