An Etymological Dictionary of the German Language/Annotated/Sklave
Sklave, masculine, ‘slave,’ from late Middle High German slave, sklave, masculine, ‘slave,’ properly ‘a captive of war.’ Derived from the national designation Slave (Middle Latin Sclavus, Slavus) during the German war of annihilation against the Slavs. Anglo-Saxon wealh, ‘Celt’ and ‘slave,’ is similarly derived. The German word Sklave passed into other Teutonic and Romance languages; compare Dutch slaaf, English slave, French esclave, Italian schiavo.