G4258–προαμαρτάνω–proamartanō

And lest, when I come again, my God may humble me among you, and I shall bewail many who have sinned already, and have not repented of the uncleanness, and lewdness, and lasciviousness, which they have committed.

προημαρτηκότων proēmartēkotōn “having sinned before”

I told you before, and foretell you, as if I were present, the second time; and being absent now I write to them who heretofore have sinned, and to all others, that, if I come again, I will not spare;

προημαρτηκόσιν proēmartēkosin “having sinned before”