List of German expressions commonly used in English

• Biergarten, open-air drinking establishment.
• Blitz, taken from Blitzkrieg (lightning war). It is a team defensive play in American or Canadian football in which the defense sends more players than the offense can block.
• Delicatessen, speciality food retailer, fine foods (German spelling Delikatessen)
• Doppelgänger, literally double-goer, also spelled in English as doppelganger; a double or look-alike. However, in English the connotation is that of a ghostly apparition of a duplicate living person.
• Ersatz, replacement; usually implying an artificial and inferior substitute or imitation.
• Hamburger, sandwich with a meat patty and garnishments.
• Hinterland
• Iceberg (German Eisberg)
• kaput (German spelling: kaputt), out-of-order, broken.
• Karabiner, snaplink, a metal loop with a sprung or screwed gate, used in climbing and mountaineering; modern short form/derivation of the older word ‘Karabinerhaken’; translates to ‘riflehook’. The German word can also mean Carbine.
• Kindergarten, literally children’s garden; day-care centre, playschool, preschool.
• Kitsch, cheap, sentimental, gaudy items of popular culture.
• Kohlrabi, type of cabbage.
• Muesli, breakfast cereal (German spelling: Müesli or Müsli).
• Neanderthal (modern German spelling: Neandertal), for German Neandertaler, meaning “of, from, or pertaining to the Neandertal (“Neander Valley”)”, the site near Düsseldorf where early Homo neanderthalensis fossils were found.
• Nein — no.
• Noodle, from German Nudel, a type of food; a string of pasta.
• Poltergeist, literally noisy ghost; an alleged paranormal phenomenon where objects appear to move of their own accord.
• Poodle, from German Pudel, breed of dog.
• Pretzel (Standard German spelling: Brezel), flour and yeast based pastry.
• Pumpernickel, type of sourdough rye bread, strongly flavoured, dense, and dark in colour.
• Quartz (German Quarz)
• Sauerkraut (sometimes shortened to Kraut), fermented cabbage.
• Schadenfreude, joy from pain (literally harm joy); delight at the misfortune of others.
• Schnaps, distilled beverage.
• Spritzer, chilled drink from white wine and soda water (from spritzen = to spray).
• Strudel (e. g. Apfelstrudel, milk-cream strudel), a filled pastry.
• uber, über, over; used to indicate that something or someone is of better or superior magnitude, e.g. Übermensch.
• verboten, prohibited, forbidden.
• Wanderlust, the yearning to travel.
• Wiener, hot dog (from Wiener Würstchen = Viennese sausage).
• Wunderkind, literally wonder child; a child prodigy.
• Zeitgeist, spirit of the time.

From Wikipedia