ἀμετάβολος
From LSJ
ἵνα οὖν μηδ' ἐν τούτῳ δῷ αὐτοῖς λαβήν (Photius, Fragments on the Epistle to the Romans 483.26) → so that he doesn't give them even here a handle (= an opportunity for refutation)
English (LSJ)
ον, = foreg., Plu.Mar.42. 2 Music, without modulation, σύστημα Aristid.Quint.1.8, Bacch.Harm.74; ἁρμονία Plu.2.437d ἀμετά-γνωστος, ον, unalterable, implacable, μῖσος J.AJ16.10.1. 2 not to be repented of, ἡδονή Max.Tyr.1.4.