Where does “Catharism” come from?

Catharism (English) comes from English ism, from English -ism, from Latin -ismus, from Ancient Greek -ισμός, from Ancient Greek -μός, from Proto-Indo-European -mós — Creates action/result nouns from verb stems.

Catharism (English): A Christian religious sect of mediaeval Europe, with dualistic and gnostic elements; condemned as a heresy by Pope Innocent III in 1209

Definitions

  1. A Christian religious sect of mediaeval Europe, with dualistic and gnostic elements; condemned as a heresy by Pope Innocent III in 1209

Ancestry of “Catharism”, step by step

Catharism traces back through two separate lines of ancestry.

via English ism

StepLanguageWordMeaning
1EnglishismAn ideology, system of thought, or practice that...
2English-ismUsed to form nouns of action or process or result...
3Latin-ismus-ism
4Ancient Greek-ισμόςForms abstract nouns
5Ancient Greek-μόςForms abstract nouns
6Proto-Indo-European-mósCreates action/result nouns from verb stems

via English cathar

StepLanguageWordMeaning
1EnglishcatharA member of certain so self-styled Novatian and other medieval Christian sects embracing a form of dualism and extraordinary practices purportedly adhering to Mary Magdalene's teachings, persecuted by Roman Catholics as heretics
2Medieval LatinCatharithe Pure
3Ancient Greekκαθαρόςclean, clear, pure
Every word from Proto-Indo-European -mósEvery word from English -ismEvery word from English ism