a suffix forming personal nouns corresponding to Latin adjectives ending in -arius or English adjectives or nouns ending in -ary ( librarian; proletarian; Rotarian; seminarian; sexagenarian; veterinarian ); subsequently productive in English with other Latinate stems, forming nouns denoting a person who supports, advocates, or practices a doctrine, theory, or set of principles associated with the base word: authoritarian; establishmentarian; totalitarian; vegetarian.
[ -ari ( us ) or -ARY + -AN ]