From a (as a negative particle) and a derivative of diakrino; properly, undistinguished, i.e. (actively) impartial -- without partiality.
see GREEK a
see GREEK diakrino
1. undistinguished and undistinguishable: φωνή, Polybius 15, 12, 9; λόγος, Lucian, Jup. Trag. 25; for בֹּהוּ, Genesis 1:2 Symm.
2. without dubiousness, ambiguity, or uncertainty (see διακρίνω, passive and middle 3 (others without variance, cf. διακρίνω, 2)): ἡ ἄνωθεν σοφία, James 3:17 (Ignatius ad Eph. 3, 2 [ET] Ἰησοῦς Χριστός τό ἀδιάκριτον ἡμῶν ζῆν (yet others take the word here, equivalent to inseparable, cf. Zahn in Patr. Apost. Works, edition Gebh., Ham. and Zahn, fasc. ii., p. 7; see also in general Zahn, Ignatius, p. 429 note{1}; Lightfoot on Ignatius, the passage cited; Sophocles Lexicon, under the word. Used from Hippocrates down.)).