Utterly alone, forsaken.
Utterly alone, forsaken — the profoundest loneliness, the strongest “alone” in German.
The most intense member of the loneliness family. Grimm's dictionary records an explicit intensity ladder: einsam → allein → ganz allein → mutterallein → mutterseelenallein. Unlike chosen, neutral solitude, it is never positive — it is desolate, forsaken, emotionally heavy (“er stand mutterseelenallein da”).
Surface-literally Mutter “mother” + Seele “soul” + allein “alone”; but the true core is the old Mutterseele = Menschenseele (“a single human soul, a person”) + allein — “forsaken by every human soul.”
Per Duden: to older Mutterseele = “human soul, person,” literally “alone of all people, abandoned by all humans.” The Mutter- element is an intensifying prefix (as in mutternackt, “stark naked”), not literal.
Long-standing as the superlative “alone.” The colorful claim that it comes from French moi tout seul (“me all alone”), via Huguenot immigrants, is discredited: the form mutterallein is attested earlier (Grimm cites it in 1522) than the Huguenots' arrival (~1600).
The romantic but false French/Huguenot “moi tout seul” origin story circulates widely and should be cited only as a debunked folk etymology. The “alone as one's mother's soul” poetic gloss is charming but misleading — the true sense is “forsaken by every human soul.”