Probably from ago; deserving, comparable or suitable (as if drawing praise) -- due reward, meet, (un-)worthy.

see GREEK ago

ἀξία (axia) − 6 Occurrences

ἄξιοι (axioi) − 4 Occurrences

ἄξιον (axion) − 9 Occurrences

ἄξιος (axios) − 19 Occurrences

ἀξίους (axious) − 3 Occurrences