Judaism is the oldest of the three major Abrahamic religions. Its adherents are called Jews. To non-religious Jewish people, Judaism is their ethnic group, culture or heritage.

How the name of the religion became "Judaism" instead of "Jewism" is unclear, but both words as they sound are obviously derived from ''Judah'', the English translation of the Hebrew name ''Yehuda''.

''Jewism'' is not a well established word in literary English, even though ''Jew'' is the first syllable of the word ''Judaism'', which entered the English language before the Modern Era. The Greeks, the first Europeans to encounter Jews, called their monotheistic religion ''Ioudaismos''. It later became ''Judaismus'' in Latin, the language of the Roman Empire, which reached Britain and Ireland during the empire's peak and later through the French language during the Norman Conquest

The horrific Jewish Holocaust made "Jew" and "Judaism" household terms around the world. Because of this, it is now considered unacceptable to call the Jewish religion "Jewism." Some people would think it's a natural progression from the word "Jew," hence the origin of the colloquialism. In this case, the word is a sign of ignorance, but not deregatory.

"Jewism" becomes a racist term, when it's used with malice by people who know that "Judaism" is the correct word to use.