Usage: 4 forms in 4 verses
Form Translated As     In Verse(s)
δευτερεύων being second LXX.Esth.4.8
δευτερεύουσι being second LXX.2Kgs.23.4
δευτερεύοντα being second LXX.Jer.52.24
δευτερεύον second LXX.2Chr.35.24

Liddell-Scott-Jones

δευτερεύω (deutereuō) be second G:V

δευτερεύω-εύω,

to be second, οὐδενός [Refs 2nd c.BC+]; δ. τινός to be next best to it, [Refs 1st c.AD+]to play second to.., [LXX+1st c.AD+]

LSJ Scripture Refs: LXX.Esth.4.8