(law) An accusation or charge brought against someone, especially by an informer; the act of accusing someone.
2012, Bradford E. Hinze, Chapter 1: A Decade of Disciplining Theologians, Richard R. Gaillardetz (editor), When the Magisterium Intervenes, Liturgical Press (Michael Glazier), page 9,
Delations frequently come from a local bishop, but there have been cases where vigilante groups (e.g., Catholics United for the Faith) and individuals have complained about a theologian's writings or lectures.