Gelassenheit, from a verb meaning to let go, is the state of the soul that has abandoned its own will and lets God be God in it. Eckhart paired it with detachment, abgeschiedenheit. The word passed into German mysticism and pietism, and Heidegger later used it for a non-grasping relation to things.
Gelassenheit
Releasement or letting-be: Meister Eckhart’s word for the soul that has let go of self and will.
Also: releasement, abgeschiedenheit