Etymological fallacy

An etymological fallacy is an argument of equivocation, arguing that a word is defined by its etymology, and that its customary usage is therefore incorrect.

History
Ancient Greeks believed that there was a "true meaning" of a word, distinct from common use. There is evidence that a similar belief existed among ancient Vedic scholars. In modern days, this fallacy can be found in some arguments of language purists.

Occurrence and examples
An etymological fallacy becomes possible when a word's meaning shifts over time from its original meaning. Such changes can include a narrowing or widening of scope or a change of connotation (amelioration or pejoration). In some cases, modern usage can shift to the point where the new meaning has no evident connection to its etymon.

Antisemitism
The term antisemitism, as coined by the Göttingen School of History in the 18th century, refers to anti-Jewish beliefs and practices. The etymological fallacy arises when a speaker asserts its meaning is the one implied by the structure of the word—racism against the Semitic people.

Some sources such as the Encyclopædia Britannica still consider it a misnomer.