Nazi

1930, from German Nazi, a clipping of Nationalsozialist (“National Socialist”) (1924), earlier attestation (1903) as shortening of national-sozial), since in German the nati- in national /ˌnatsi̯oˈnaːl/ is approximately pronounced Nazi [ˈnäːtsi]; compare the parallel pejorative terms Sozi (“socialist, social democrat”), Kozi (“commie, commo, communist”).

A homonymic term Nazi was in use before the rise of the NSDAP in Bavaria as a pet name for Ignaz and (by extension from that) a derogatory word for a backwards peasant, which may have influenced the use of that abbreviation by the Nazis' opponents and its avoidance by the Nazis themselves.