ὑπογάιδιον
From LSJ
διὸ καὶ μεταλάττουσι τὴν φυσικὴν χρῆσιν εἰς τὴν παρὰ φύσιν αἱ δοκοῦσαι παρθένοι τῶν εἰδώλων → therefore those professing to be virgins of the idols even change the natural use into the unnatural (Origen, commentary on Romans 1:26)
English (LSJ)
ὑπόγειον τύμβον, Hsch. (fort. -γαΐδιον, cf. καταγαΐδιοι).