Is there any textual evidence from the Koine period of ἐντροπή σοι! / ἐντροπὴ ὑμῖν! "Shame on you!" or ἐντροπὴ αὐτῷ! / ἐντροπὴ αὐτῇ / ἐντροπὴ αὐτοῖς! / ἐντροπὴ αὐταῖς!1 Corinthians 6:5, 15:34 wrote:Πρὸς ἐντροπὴν ὑμῖν λέγω.
I remember the first time I blushed (κόκκινος ἐγενόμην, ἐκοκκίνισα) in Greek was when my foreign teacher chided me with "Ντροπή σου, Στέφανε!" for not bringing my homework or something like that. I'm guessing that if the Corinthians had been brought up blushing to their parents and teachers chiding with "ἐντροπή σοι!", then they would, likely as not, involuntarily blush here or be moved to childish tears at Paul's words too.
Evidence from Modern Greek is great in itself, but even better if there is some textual evidence from our actual period.