-arian

-arian

suff.
Believer in; advocate of: utilitarian.

[Latin -ārius, -ary + -an.]

-arian

suffix forming nouns
indicating a person or thing that advocates, believes, or is associated with something: vegetarian; millenarian; librarian.
[from Latin -ārius -ary + -an]

Ar•i•an

(ˈɛər i ən, ˈær-)

adj.
1. of or pertaining to Arius or Arianism.
n.
2. an adherent of Arianism.
[1525–35; < Late Latin]

-arian

a suffix forming personal nouns corresponding to Latin adjectives ending in -ārius or English adjectives or nouns ending in -ary (librarian; proletarian); subsequently productive in English with other Latinate stems, forming nouns denoting a person who supports, advocates, or practices a doctrine, theory, etc., associated with the base word: authoritarian; vegetarian.
[< Latin -āri(us) or -ary + -an1]