ἀμετάθετος
From LSJ
Τοὺς δούλους ἔταξεν ὡρισμένου νομίσματος ὁμιλεῖν ταῖς θεραπαινίσιν → He arranged for his male slaves to have sex with female slaves at a fixed price (Plutarch, Life of Cato the Elder 21.2)
English (LSJ)
ον,
A unalterable, immutable, κατάληψις, of knowledge, Zeno Stoic.1.20; of fate, Chrysipp.ib.2.264, cf. Plb.30.17.2; ἀκίνητα καὶ ἀ. OGI331 (Pergam.), etc. Adv. -τως, διακεῖσθαι D.S.1.83, cf. Ascl.in Metaph. 22.6. 2 Gramm., not inflected, A.D.Synt.322.1.