ἐνδείκνυσθαι
From LSJ
αὐτὸν κέκρουκας τὸν βατῆρα τοῦ λόγου → you have struck the very threshold of the argument, you have struck the most important and chiefmost point
Greek > English (Woodhouse Verbs Reversed)
(see also ἐνδείκνυμι): display, exhibit, prove, show, give proof of, make a display of
Lexicon Thucydideum
demonstrare, ostentare, to point out, display, 4.126.6, 8.82.3.