διισχυρίζεσθαι
From LSJ
Νέος πεφυκὼς πολλὰ χρηστὰ μάνθανε → Dum floret aetas, disce, quod scitum decet → In jungem Alter lerne viel, was brauchbar ist
Greek > English (Woodhouse Verbs Reversed)
(see also διισχυρίζομαι): affirm, assert, assert confidently, assert dogmatically, assert emphatically, assert positively, assert vigorously, contend that, maintain an opinion, press one's views, protest in argument, urge strongly