That the Greek word is used should not be surprising since the New Testament and near all of the patristic theology was written in that language. I don’t understand your puzzlement.
Not puzzlement: mockery (though not at you). The other addressees have been putting forth the notion that some concepts, not words, cannot be understood apart from knowing the original language.
One specifically made the claim I would understand how apostasy is dependent on what bishop you answer to if only I understood a particular greek word.