Lewis & Short

dēlātor, ōris, m. [defero, ], an accuser, informer, denouncer (only post-Aug.; esp. freq. in Tacit. and Suet.): judicesdelatores, Quint. 9, 2, 74; cf. 3, 10, 3: delatorum judicium, quasi latronum, Plin. Pan. 34, 1 sq.; 35, 1; Suet. Tib. 45; 61; Tac. A. 6, 40; id. H. 1, 2 et saep.: majestatis, i. e. of hightreason, Tac. A. 2, 50; cf.: Papiae legis, i. e. one who denounces a violation of it, Suet. Ner. 10.