[ahd-vaw-kah-toos dee-ah-baw-lee] 
advocatus diaboli
in the Roman Catholic church, the promoter of the faith, who critically examines the life of and miracles attributed to an individual proposed for beatification or canonization. He is popularly called the devil's advocate because his presentation of facts includes everything unfavourable to the candidate. Pope Leo X, in the early 15th century, seems to have introduced the term, but Sixtus V formally established the office in 1587. The office was abolished when Pope John Paul II revised the canonization procedures in 1979.
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vɔˈkɑ