Whereby the world that then was, being overflowed with water, perished:
Berean Study Bible (BSB) - 2 Peter 3:6 >through which the world of that time perished in the flood.
Textus Receptus (TR) - 2 Peter 3:6 >δι᾿ ὧν ὁ τότε κόσμος ὕδατι κατακλυσθεὶς ἀπώλετο·