fugemirth
noun
The fleeting joy of a singular, wonderful moment, aware that its end is near, and knowing that someday you'll reflect on this happiness with nostalgia. It's the bittersweet mix of enjoyment and the future longing that such days inevitably inspire.
A blend of Latin 'fugere' (to flee) + Old English 'myrþ'* (mirth, joy), depicting a mirthful moment that is escaping even as it is experienced. Pronounced "FYOO-juh-mirth"