Antisemitism is enmity against Jews. Those who are anti-Semites think that Jews are evil people. Some anti-Semites only have a bad opinion of Jews; other anti-Semites demand that Jews should be killed.
The term antisemitism comes from the word "Semite". According to the Bible, Noah had three sons. One of them was called Sem, and he allegedly became the ancestor of the Jews. In linguistics, the term "Semitic" is known in certain languages: in addition to the Hebrew of the Jews, this is also Arabic, for example. "Anti" is a Greek word that means "against".
People have held prejudices against Jews since the Middle Ages. Their opinion was that Jews are not tolerant of other gods because the Jews only wanted to recognize one god. In the Middle Ages, Jews were accused of not being Christians. The Jews had different customs and laws.
Antisemites have said that Jews poison wells, and that they kidnap and drink the blood of children. These rumors are false.
After the 18th century another reason to be against Jews was added. People claimed that Jews were an entirely different species and that they were dangerous as they wanted to rule the world. This type of antisemitism is called racial antisemitism. One of the most famous antisemites was Adolf Hitler. His Nationalists governed Germany from 1933 till 1945. First, they started mistreating German Jewish people, then they murdered 6 million Jewish people all over Europe. This crime is known as the Holocaust.