Hiwi (ˈhiːviː), the German abbreviation of the word Hilfswilliger or, in English, auxiliary volunteer, designated, during World War II, a member of different kinds of voluntary auxiliary forces made up of recruits indigenous to the territories of Eastern Europe occupied by Nazi Germany. Adolf Hitler reluctantly agreed to allow recruitment of Soviet citizens in the Rear Areas during Operation Barbarossa. In a short period of time, many of them were moved to combat units.
Hiwis comprised 50% of the 2nd Panzer Army's 134th Infantry Division in late 1942, while the 6th Army at the Battle of Stalingrad was composed of 25% Hiwis. By 1944, their numbers had grown to 600,000. Both men and women were recruited. Veteran Hiwis were practically indistinguishable from regular German troops, and often served in entire company strengths.
Between September 1941 and July 1944 the SS employed thousands of collaborationist auxiliary police recruited as Hiwis directly from the Soviet POW camps. After training, they were deployed for service with Nazi Germany, in the General Government, and the occupied East.
In one instance, the German SS and police inducted, processed, and trained 5,082 Hiwi guards before the end of 1944 at the SS training camp division of the Trawniki concentration camp set up in the village of Trawniki southeast of Lublin. They were known as the "Trawniki men" (Trawnikimänner) and were former Soviet citizens, mostly Ukrainians. Trawnikis were sent to all major killing sites of the "Final Solution", which was their training's primary purpose. They took an active role in the executions of Jews at Bełżec, Sobibor, Treblinka II, Warsaw (three times), Częstochowa, Lublin, Lvov, Radom, Kraków, Białystok (twice), Majdanek as well as Auschwitz, and Trawniki itself.
The term 'Hiwis' acquired a thoroughly negative meaning during World War II when it entered into several other languages in reference to Ostlegionen as well as volunteers enlisted from occupied territories for service in a number of roles including hands-on shooting actions and guard duties at extermination camps on top of regular military service, drivers, cooks, hospital attendants, ammunition carriers, messengers, sappers, etc.