zealot

Etymology

Initially only found as Middle English zelote, an epithet of Simon the Zealot, acquiring its current senses in the 16th and 17th centuries. The Middle English derives from Latin zēlōtēs, from Ancient Greek ζηλωτής (zēlōtḗs, “emulator, zealous admirer, follower”), from ζῆλος (zêlos, “zeal, jealousy”), from ζηλόω (zēlóō, “to emulate, to be jealous”).

noun

1. One who is zealous, one who is full of zeal for his own specific beliefs or objectives, usually in the negative sense of being too passionate; a fanatic.
2. (historical) A member of a radical, warlike, ardently patriotic group of Jews in Judea, particularly prominent in the first century, who advocated the violent overthrow of Roman rule and vigorously resisted the efforts of the Romans and their supporters to convert the Jews.
3. (historical) A member of an anti-aristocratic political group in Thessalonica from 1342 until 1350.