ματαιόω
From LSJ
ἀκίνδυνοι δ' ἀρεταὶ οὔτε παρ' ἀνδράσιν οὔτ' ἐν ναυσὶ κοίλαις τίμιαι → but excellence without danger is honored neither among men nor in hollow ships
English (LSJ)
A bring to naught, Sch.S.Tr.258, Gloss. 2 ματαιοῦσιν ἑαυτοῖς ὅρασιν invent a vision of their own, LXX Je.23.16. II more freq. in Pass., to be brought to naught, οὐ ματαιωθήσεται τὰ ῥήματα ib.Ju.6.4. 2 become foolish, act foolishly, ἐματαιώθην σφόδρα ib.1 Ch.21.8, cf. Ep.Rom.1.21; μεματαίωταί σοι thou hast done foolishly, LXX 1 Ki.13.13.
Greek (Liddell-Scott)
ματαιόω: ἴδε ματαιόομαι.