Semitism is a term that can have different meanings depending on the context. Here are some of the definitions and explanations found in the search results:

• Semitism: Semitic character or qualities; a characteristic feature of a Semitic language occurring in another language; policy or predisposition favorable to Jews.
• Semitism: A word, phrase, grammatical construction, or other feature originating in or peculiar to a Semitic language.
• Semite: A member of any of a number of peoples of ancient southwestern Asia including the Akkadians, Phoenicians, Hebrews, and Arabs.
• Antisemitism: Prejudice against or hatred of Jews.
• History of the term Semite: The name Semite comes from Shem, the eldest of the three sons of Noah. In the Greek and Latin versions of the Bible, Shem becomes Sem, since neither Greek nor Latin has any way of representing the initial sound of the Hebrew name. The term "Semitic" was later used to describe a group of languages spoken in the Middle East, including Hebrew, Arabic, and Aramaic. In the 19th century, the term "Semitic" was also used to describe a group of peoples who were believed to be descended from Shem, including Jews, Arabs, and Assyrians. However, this racial definition of Semitism has been discredited.

In summary, Semitism can refer to Semitic character or qualities, a characteristic feature of a Semitic language, or a policy or predisposition favorable to Jews. Antisemitism, on the other hand, refers to prejudice against or hatred of Jews. The term Semite originally referred to a group of languages spoken in the Middle East and later to a group of peoples who were believed to be descended from Shem, but this racial definition has been discredited.