αχρηστία
From LSJ
συνερκτικός γάρ ἐστι καὶ περαντικός, καὶ γνωμοτυπικὸς καὶ σαφὴς καὶ κρουστικός, καταληπτικός τ' ἄριστα τοῦ θορυβητικοῦ → he's intimidative, penetrative, aphoristically originative, clear and aggressive, and superlatively terminative of the obstreperative
