Amish
mid 19th century: apparently from German amisch, from the name Jakob Amman.
wiktionary
From Pennsylvania German Amisch or German Amische, after the name of the Swiss preacher Jakob Amman (1645-1730). The surname is a contraction of Old High German ambahtman.
etymonline
Amish (adj.)
1844, American English, from the name of Jacob Amman, 17c. Swiss Mennonite preacher who founded the sect. The surname is a contraction of Old High German ambahtman, title of an official in the German Swiss cantons, from ambet "office" (German Amt; see amt), a Celtic borrowing related to the beginning of ambassador) + man "man." Originally also spelled Omish, which reflects the pronunciation in Pennsylvania German dialect. As a noun, by 1884. Other early names for the sect were Ammanite and, in a European context, Upland Mennonite.
