From kata and agora; against one in the assembly, i.e. A complainant at law; specially, Satan -- accuser.
see GREEK kata
see GREEK agora
STRONGS NT 2725: κατήγωρκατήγωρ, ὁ, an accuser: Revelation 12:10 G L T WH. It is a form unknown to Greek writers, a literal transcription of the Hebrew קָטִיגור, a name given to the devil by the rabbis; cf. Buxtorf, Lex. Chaldean talm. et rahb., p. 2009 (p. 997, Fischer edition); (Schöttgen, Horae Hebrew i., p. 1121f; cf. Buttmann, 25 (22)).