“hiraeth”
— (hɨraɪ̯θ), noun | A Welsh, untranslatable feeling, hiraeth is loosely described as a homesickness for a home you cannot return to anymore or a place, which never even existed. Connotations of sadness, yearning, profound nostalgia, and wistfulness are imbued into the state of hiraeth. Overall this beautiful, but painful longing is a an expression of an empty desire and grief over a past life or place. It is the ultimate signifier of a bond, which has ceased to exist.


(I saw this word, and I think it was quite interesting.)