n.
the feeling of returning from an immersive trip only to notice it fading rapidly from your awareness, as if your brain had automatically assumed it was all just a dream and already went to work scrubbing it from your memory.
German rückkehren, coming back + Unruhe, restlessness. Compare Zugunruhe, “migration restlessness,” the fidgety behavior observed in birds approaching migration. Pronounced “rook- kair-oon-roo-uh.”