Antisemitism "is especially inappropriate as a label for the anti-Jewish prejudices, statements, or actions of Arabs or other Semites," Encyclopedia Britannica says in its definition of antisemitism.
It is unclear from the article's edit history when this part of the definition was added. Encyclopedia Britannica's online entry does not offer an alternative term for prejudice by Arabs and Semitic people against Jews.
"Although the term [antisemitism] now has wide currency, it is a misnomer, since it implies a discrimination against all Semites. Arabs and other peoples are also Semites, and yet they are not the targets of antisemitism as it is usually understood," asserts the online encyclopedia.
Excluding Arabs and Semitic people from being labeled antisemitic because of their "Semitism" is what is called a "etymological fallacy" -- When the archaic root words or original meaning of a term are used to make an argument about the current meaning or even the generally accepted definition.
It is a common argument made by some that their actions or beliefs are not antisemitic, because they themselves are Semitic.
The term "Semitic" can be used in a technical-linguistic sense or to refer to ethnic groups. Hebrew, Arabic and Aramaic are all considered Semitic languages.
While Encyclopedia Britannica calls the term "antisemitism" a "misnomer," it has historically only implied a dislike and/or hatred of Jews because it was coined in the 19th century with this sole considered meaning. It was never intended to apply to all Semitic peoples.
According to the International Holocaust Remembrance Alliance (IHRA), the unhyphenated spelling (i.e. antisemitism vs. anti-Semitism) "is favored by many scholars and institutions in order to dispel the idea that there is an entity ‘Semitism’ which ‘anti-Semitism’ opposes. Antisemitism should be read as a unified term so that the meaning of the generic term for modern Jew-hatred is clear. At a time of increased violence and rhetoric aimed towards Jews, it is urgent that there is clarity and no room for confusion or obfuscation when dealing with antisemitism."
There is no definitive definition of antisemitism, though recently the IHRA working definition, the Jerusalem Definition of Antisemitism, and the lesser-known Nexus definition were developed to create common understandings of the term. The IHRA definition has gained the support of dozens of countries and hundreds of institutions. Each definition has various guidelines to explain their definition. The main contentions between these three leading definitions is largely about Israel, and if anti-Zionism is antisemitism. None of the leading definitions assert that antisemitism cannot be used as a label for Jew-hatred from Arabs and Semitic peoples.