Sehnsucht
Etymology
German, joining "sehnen" ("to long, to pine") with "Sucht" ("craving, addiction," historically tied to the old word for sickness, "siech"). The literal sense is roughly a "longing-addiction." Romantic writers made it central, and C.S. Lewis later popularized it in English as a name for an unsatisfied desire more desirable than any satisfaction.
noun · /ZAYN-zookht/
An intense, bittersweet longing for something you can’t quite name or ever fully reach.
What it names
The yearning itself — aimed at no fixed object, pointed somewhere just beyond life as you know it.
Example
Standing at the train window, she was overcome by a sehnsucht for a home she wasn’t sure existed.
Related idea
Where nostalgia longs for a real past, sehnsucht longs for something never possessed and perhaps unreachable.