Merriam-Webster wrote:
Definition of ANTI-SEMITISM : hostility toward or discrimination against Jews as a religious, ethnic, or racial group
That should settle the matter; but in the interest of a fuller discussion, here are some excerpts from the Wikipedia article with my own emphasis added.
I recommend reading the entire article highly; the photograph at the head of the entry is particularly illuminating, and may indeed seem familiar -- as might some of the themes I have highlighted below:
Wikipedia wrote:
Antisemitism (also spelled anti-semitism or anti-Semitism) is prejudice against or hostility towards Jews often rooted in hatred of their ethnic background, culture, and/or religion. In its extreme form, it "attributes to the Jews an exceptional position among all other civilizations, defames them as an inferior group and denies their being part of the nation[s]" in which they reside. A person who holds such views is called an "antisemite"....
While the term's etymology might suggest that antisemitism is directed against all Semitic peoples, the term was coined in the late 19th century in Germany as a more scientific-sounding term for Judenhass ("Jew-hatred"), and that has been its normal use since then.
....from the 1990s, some writers claim to have identified a new antisemitism, a form of antisemitism coming simultaneously from the far left, the far right, and radical Islam, which tends to focus on opposition to Zionism and a Jewish homeland in the State of Israel, and which may deploy traditional antisemitism motifs, including older motifs....
Holocaust denial and Jewish conspiracy theories are also considered a form of antisemitism.
....Despite the use of the prefix anti-, the terms Semitic and anti-Semitic are not directly opposed to each other. Antisemitism refers specifically to prejudice against Jews alone and in general, despite the fact that there are other speakers of Semitic languages (e.g. Arabs, Ethiopians, or Assyrians) and that not all Jews speak a Semitic language. The term anti-Semitic has been used on occasion to include bigotry against other Semitic-language peoples such as Arabs, but such usage is not widely accepted.
Though the general definition of antisemitism is hostility or prejudice against Jews, a number of authorities have developed more formal definitions.... Holocaust scholar and City University of New York professor Helen Fein defines it as "a persisting latent structure of hostile beliefs towards Jews as a collective manifested in individuals as attitudes, and in culture as myth, ideology, folklore and imagery, and in actions – social or legal discrimination, political mobilization against the Jews, and collective or state violence – which results in and/or is designed to distance, displace, or destroy Jews as Jews." Elaborating on Fein's definition, Dietz Bering of the University of Cologne writes that, to antisemites, "Jews are not only partially but totally bad by nature, that is, their bad traits are incorrigible. Because of this bad nature: (1) Jews have to be seen not as individuals but as a collective. (2) Jews remain essentially alien in the surrounding societies. (3) Jews bring disaster on their 'host societies' or on the whole world, they are doing it secretly, therefore the antisemites feel obliged to unmask the conspiratorial, bad Jewish character." Bernard Lewis defines antisemitism as a special case of prejudice, hatred, or persecution directed against people who are in some way different from the rest. According to Lewis, antisemitism is marked by two distinct features: Jews are judged according to a standard different from that applied to others, and they are accused of "cosmic evil." Thus, "it is perfectly possible to hate and even to persecute Jews without necessarily being anti-Semitic" unless this hatred or persecution displays one of the two features specific to antisemitism.
There have been a number of efforts by international and governmental bodies to define antisemitism formally.... In 2005, the European Monitoring Centre on Racism and Xenophobia (now Fundamental Rights Agency), then an agency of the European Union, developed a more detailed definition: "Antisemitism is a certain perception of Jews, which may be expressed as hatred toward Jews. Rhetorical and physical manifestations of antisemitism are directed toward Jewish or non-Jewish individuals and/or their property, toward Jewish community institutions and religious facilities. In addition, such manifestations could also target the state of Israel, conceived as a Jewish collectivity. Antisemitism frequently charges Jews with conspiring to harm humanity, and it is often used to blame Jews for 'why things go wrong'."
It then listed "contemporary examples of antisemitism in public life, the media, schools, the workplace, and in the religious sphere." These included: "Making mendacious, dehumanizing, demonizing, or stereotypical allegations about Jews; accusing Jews as a people of being responsible for real or imagined wrongdoing committed by a single Jewish person or group; denying the Holocaust; and accusing Jewish citizens of being more loyal to Israel, or to the alleged priorities of Jews worldwide, than to the interests of their own nations.
It also listed ways in which attacking Israel could be antisemitic:
• Denying the Jewish people the right to self-determination, e.g. by claiming that the existence of a state of Israel is a racist endeavor;
• Applying double standards by requiring of Israel a behavior not expected or demanded of any other democratic nation;
• Using the symbols and images associated with classic anti-Semitism (e.g. claims of Jews killing Jesus or blood libel) to characterize Israel or Israelis;
• Drawing comparisons of contemporary Israeli policy to that of the Nazis;
• Holding Jews collectively responsible for actions of the State of Israel.
The definition added that criticism of Israel cannot be regarded as antisemitism so long as it is "similar to that leveled against any other country."
There is much more: the section on antisemitism in the Middle East is especially interesting and probative.
"Semitic" does indeed refer to peoples other than Jews; but there is no such thing as "Semitism," and claiming that "antisemitism" means anything other than hatred of Jews is akin to claiming that "anti-Americanism" could refer to antipathy toward Canada, Mexico and Brazil. In other words, it's ludicrous.
I DO hope that this puts this bit of misdirection and obfuscation of the obvious meaning of this term to rest. I'll decline to speculate on why anyone would make such a hobbyhorse of it, repeatedly trying to devalue or dismiss antisemitism, that is, the hatred of and prejudice against Jews, as a concept that is somehow illegitimate or not worthy of attention. Since no sane person, surely, would claim that no such thing as antisemitism exists, one wonders why there would or could be any objection to the word, the meaning of which has been perfectly clear and commonly and unambiguously understood for well over a hundred years. Should there be no word for antisemitism? Does antisemitism not exist? Is antisemitism somehow irrelevant to the debate about a part of the world where it is actively promoted and encouraged by governments and religious institutions? As I say, one wonders what the point of these posts might have been, and the motivation behind them -- but, as I say, I shall not speculate.