Abbott-Smith Manual Greek Lexicon
ματαιότης (G3153)
3 † ματαιότης , -ητος, ἡ ( μάταιος ), [in LXX for הֶבֶל , Ps 30 (31):6 38 (39):5 61 (62):9 , al., and nearly 40 times in Ec; for שָׁוְא , Ps 25:4 , al.; רִיק , etc.;] vanity , emptiness , frailty , folly : Ro 8:20 , II Pe 2:18 ; τ. νοός , Eph 4:17 (elsewhere only in Pollux, 6, 134, and Eccl.).†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain