ἀγνωμ-οσύνη · agnōm-osynē — LSJ
want of acquaintance with a thing, Pl. Tht. 199d.
want of sense, folly, Thgn. 896, Democr. 175; senseless pride, arrogance, Hdt. 2.172, E. Ba. 885 (lyr.); πρὸς ἀ. τραπέσθαι Hdt. 4.93; ἀγνωμοσύνῃ χρᾶσθαι Id. 5.83; ὑπʼ ἀγνωμοσύνης Id. 9.3.
want of feeling, unkindness, D. 18.252; θεῶν ἀ. S. Tr. 1266 (dub.); ἀ. τύχης, Lat. iniquitas fortunae, D. 18.207.
in pl., misunderstandings, X. An. 2.5.6.