1847, "a Jew, Arab, Assyrian, or Aramaean" (an apparently isolated use from 1797 refers to the Semitic language group), back-formation from Semitic or else from French Sémite (1845), from Modern Latin Semita, from Late Latin Sem "Shem," one of the three sons of Noah (Genesis x.21-30), regarded as the ancestor of the Semites (in old Bible-based anthropology), from Hebrew Shem. In modern sense said to have been first used by German historian August Schlözer in 1781.
word-forming element making nouns implying a practice, system, doctrine, etc., from French -isme or directly from Latin -isma, -ismus (source also of Italian, Spanish -ismo, Dutch, German -ismus), from Greek -ismos, noun ending signifying the practice or teaching of a thing, from the stem of verbs in -izein, a verb-forming element denoting the doing of the noun or adjective to which it is attached. For distinction of use, see -ity. The related Greek suffix -isma(t)- affects some forms.
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<a href="https://www.etymonline.com/word/Semitism">Etymology of Semitism by etymonline</a>
Harper, D. (n.d.). Etymology of Semitism. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/Semitism