Anti-Semitism is racism. No ifs, no buts. It's hostility to, or prejudice, against Jews.
There are some who have suggested that anti-Zionism - the opposition to a Jewish-majority state in Palestine - is also a form of anti-Semitism.
While some anti-Zionists do cross the line into anti-Semitism, many, including Jewish anti-Zionists, make clear their criticism is of Israel, not of the Jewish people. They make a distinction between Jewish people and Israel's policies.
In this week's Reality Check, Mehdi Hasan explains why conflating Israel with Jews is wrong, and how it's sometimes Israeli leaders who do this conflating.