ἀχρεῖος
I. "useless, unprofitable, good for nothing", Hes., Soph., etc.
2. esp. "unserviceable, unfit for war", Hdt.; τὸ ἄχρ. τοῦ στρατοῦ "the unserviceable part" of an army, id=Hdt., Thuc., etc.
II. in Hom. neut. ἀχρεῖον as adv., ἀχρεῖον ἰδών giving a "helpless" look, looking "foolish", of Thersites after being beaten, Il.; ἀχρεῖον ἐγέλασσε laughing "without cause or meaning", laughed with a "forced" laugh, Od.; so, ἀχρεῖον κλάζειν to bark "without cause", Theocr.