saudade – a melancholic longing or yearning…“a vague and constant desire for something that does not and probably cannot exist, for something other than the present.”
From Smoke Gets in Your Eyes and Other Lessons from the Crematory by Caitlin Doughty: “…a longing, tinged with nostalgia, madness, and sickness over something you have lost.”
untranslatable words – saudade