dev·il's ad·vo·cate • n. a person who expresses a contentious opinion in order to provoke debate or test the strength of the opposing arguments: the interviewer will need to play devil's advocate to put the other side's case forward. ∎  hist. the popular title of the person appointed by the Roman Catholic Church to challenge a proposed beatification or canonization, or the verification of a miracle.

Devilʾs advocate or advocatus diaboli. Person appointed by the Roman Catholic Congregation of Rites to contest the claims of those put forward for beatification or canonization (i.e. being recognized officially as saints). His more correct name is promotor fidei (promoter of the faith); the supporter of the proposal is known as advocatus Dei (advocate of God).