What does it mean to be Semitic and Anti-Semitic?

Hello people

I’m gonna start by saying I am not Jewish. I’m Mexican, and I do have some distant Jewish blood from my dad’s side of the family. A few days ago I asked in this forum about non-practicing Jews and circumcision and someone mentioned Ukraine and anti-semitism.

To my understanding, semitism is an ethnolinguistic and cultural set of groups of people. I think Semitic refers to Semitic languages, such as Arabic and Hebrew, which is part of the Afro-asiatic language family. So, if a Jewish person from Ukraine, or an Ashkenazi Jew from any part of Europe, is of European DNA and speaks Yiddish, which is a Germanic indo-european language, why are they considered Semitic? Is it because their religion comes from Semitic people?

Also, I was watching videos about Israel and Palestine, and it seems like Israelites and Palestinians wish to coexist peacefully, and it’s only a minority of both groups that are really against each other. If a Palestinian person is against Jews, would he be considered anti-semitic, even though Arabs are 100% Semitic themselves? And would a Jewish person against Arabs be considered anti-Semitic?

Thanks, and I hope to not create chaos in the comments