Angst[German]: A generalized dread or fear.

Kindergarten[German]: lit.: children’s garden.

Ersatz[German]: Something which can be used as a replacement or substitute (usually of inferior quality)

Gedankenexperiment[German]: lit.: thought experiment. Used a lot in scientific/philosophical circles.

Spannungsbogen[German]: lit.: “the span of the bow” or “a bow under tension”. Denotes the arc of tension built up in a work of literature.

..numerous others that are, however, very specific to scientific subjects.