The word antisemitism was first used in 1879 by Wilhelm Marr, a German journalist and political agitator. Marr coined the term in his pamphlet titled Der Weg zum Sieg des Germanenthums über das Judenthum ("The Way to Victory of Germanism over Judaism"). He used it to describe a new form of racial hostility toward Jews, distinct from the older, religiously based prejudice against Judaism.
Marr's term "antisemitism" was meant to give a more "scientific" or "rational" justification for anti-Jewish sentiments, as it was framed in the context of racial theory, which was becoming influential in Europe at the time. His work and the adoption of the term helped fuel the rise of modern antisemitic movements in Europe, contributing to the widespread hatred of Jews that would culminate in events like the Holocaust.
Though the word was coined in the late 19th century, the anti-Jewish prejudice it describes has existed for centuries before, rooted in theological, economic, and cultural hostility.