A.useless, unprofitable, “ἀχρήϊος ἀνήρ” Hes.Op.297; ἐπέων νομός ib.403; “δέμας” A.Pr. 365, cf. Hp.Int.39; “οἰκητήρ” S.OC627; opp. εὐγενής, Id.Fr.667; ἐρινὸς ἀ. ὢν ἐς βρῶσιν ib.181; “ἀ. κοὐ σοφός” E.Med.299; “δοῦλος” Ev.Matt.25.30; “οὐκ ἀπράγμονα ἀλλ᾽ ἀχρεῖον νομίζομεν” Th.2.40; “λόγον ἀχρεῖον ἀπέρριψαν” Ant.Lib.11.3: Comp. “-ότερος, ὄρνιθες” Chrysipp.Stoic.3.195: c. inf., unfit to do, “ἀ. πράττειν τι” Pl.R.371c: c. dat., “ἀ. τοῖς σώμασι” Agatharch.Fr.Hist.3, cf. Them.Or.26.326a.
2. esp. unfit for war, “ἀ. ὅμιλος” Hdt.3.81; τὸ ἀ. τοῦ στρατοῦ the unserviceable part of an army, Id.1.191; “οἱ ἀχρειότατοι” Th.1.93, 2.6, cf. X.HG7.2.18; “τὸ ἀ. τῆς ἡλικίας” Th.2.44. Adv. “-είως, ἔχειν πρὸς ναυμαχίαν” App.BC5.84.
II. neut. ἀχρεῖον, as Adv., twice in Hom., ἀχρεῖον ἰδών giving a helpless look, looking foolish, of Thersites after being beaten, Il.2.269; ἀχρεῖον δ᾽ ἐγέλασσε laughed without cause, made a forced laugh, of Penelope trying to disguise her feelings, Od.18.163; ἀχρεῖον κλάζειν bark without need or cause, Theoc.25.72.
III. Adv. ἀχρείως γέλασόν με (cf. ἀχρειόγελως) APl.4.86, cf. Them.Or.33.367b: neut. pl. as Adv. “ἀχρεῖ᾽ ἀσπαίροντος” helplessly, Euph.44.