G0126–ἀΐδιος–aidios

for the invisible things of Him from the creation of the world, by the things made being understood, are plainly seen, both His eternal power and Godhead -- to their being inexcusable;

ἀΐδιος aidios “eternal”

messengers also, those who did not keep their own principality, but did leave their proper dwelling, to a judgment of a great day, in bonds everlasting, under darkness He hath kept,

ἀϊδίοις aidiois “eternal”