G4768
στυγνάζω
be gloomy
στυγνάζω (στυγνός, sombre, gloomy, sullen, Isa.5:17, Wis.17:5, Dan LXX 2:12*), [in LXX: Eze.27:35 28:19 32:10 (שָׁמֵם)* ;] to have a sombre, gloomy appearance: of the human countenance (RV, his countenance fell), Mrk.10:22; of the sky (so στυγνότης, Polyb., iv, 21, 1), Mat.16:3 ([WH], R, mg., om.).† (AS)
The KJV translates G4768 in the following manner:
lowring (2x), sad (2x)
Full Thayer's lexicon entry
στυγνάζω — stygnázō
στυγνάζω; 1 aorist participle στυγνάσας; (στυγνός sombre, gloomy); to be sad, to be sorrowful: properly, ἐπί τίνι (R. V. his countenance fell at etc.), Mar 10:22; metaphorically, of the sky covered with clouds (A. V. to be towering), Mat 16:3 (T brackets WH reject the passage). (Schol. on Aeschylus Pers. 470; the Sept. thrice for שָׁמֵן, to be amazed, astonished, ἐπί τινα, Eze 27:35; Eze 32:10; στυγνότης, of the gloominess of the sky, Polybius 4, 21, 1.)
2 occurrences
Matthew (1), Mark (1)