votary n.

"solemn promise," c. 1300, from Anglo-French and Old French voe (Modern French vœu), from Latin votum "a promise to a god, solemn pledge, dedication; that which is promised; a wish, desire, longing, prayer," noun use of neuter of votus, past participle of vovere "to promise solemnly, pledge, dedicate, vow," from PIE root *wegwh- "to speak solemnly, vow, preach" (source also of Sanskrit vaghat- "one who offers a sacrifice;" Greek eukhe "vow, wish," eukhomai "I pray"). The meaning "solemn engagement to devote oneself to a religious order or life" is from c. 1400; earlier "to bind oneself" to chastity (early 14c.).

adjective and noun word-forming element, in most cases from Latin -arius, -aria, -arium "connected with, pertaining to; the man engaged in," from PIE relational adjective suffix *-yo- "of or belonging to." The neuter of the adjectives in Latin also were often used as nouns (solarium "sundial," vivarium, honorarium, etc.). It appears in words borrowed from Latin in Middle English. In later borrowings from Latin to French, it became -aire and passed into Middle English as -arie, subsequently -ary.