Abbott-Smith Manual Greek Lexicon
στυγνάζω (G4768)
2 † στυγνάζω ( στυγνός , sombre, gloomy, sullen , Is 5:17 , Wi 17:5 , Da LXX 2:12 *), [in LXX: Ez 27:35 28:19 32:10 ( שָׁמֵם )* ;] to have a sombre, gloomy appearance : of the human countenance (RV, his countenance fell ), Mk 10:22 ; of the sky (so στυγνότης , Polyb., iv, 21, 1), Mt 16:3 (|[WH]|, R, mg., om.).†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain