ἄκαμπ-τος · akamp-tos — LSJ
unbent, rigid, the part that will not bend
unbent, rigid, Hp. Fract. 2 (Sup.), Pl. Ti. 74b (Comp.), etc.; τὸ ἄ. the part that will not bend, Arist. HA 493b29.
2 unbending, unflinching
metaph., unbending, unflinching, βουλαί Pi. P. 4.72; ψυχὰν ἄ. Id. I. 4(3).53; ἀ. μένει A. Ch. 455 (lyr.); τὸ πρὸς τοὺς πόνους, τὸ εἰς ἐπιείκειαν ἄ., Plu. Lyc. 11, Cat.Mi. 4.
3 from which there is no return
from which there is no return, χῶρος ἐνέρων AP 7.467 (Antip.); τρίβος IG 12(7).449 (Amorgos).