θανάτῳ θάνατον πατήσας → trampling down death by death (lit. "having trampled down death")
Χριστὸς ἀνέστη ἐκ νεκρῶν, θανάτῳ θάνατον πατήσας, καὶ τοῖς ἐν τοῖς μνήμασι, ζωὴν χαρισάμενος → Christ is risen from the dead, trampling down death by death, and upon those in the tombs bestowing life
https://en.wikipedia.org/wiki/Paschal_troparion