A prolonged form of an apparently primary verb; to extinguish (literally or figuratively) -- go out, quench.
STRONGS NT 4570: σβέννυμισβέννυμι (ζβέννυμι, 1 Thessalonians 5:19 Tdf. (cf. Sigma)) and (in classics) σβεννύω; future σβέσω; 1 aorist ἐσβεσα; passive, present σβεννυμαι; from Homer down; the Sept. for כִּבָּה and דָּעַך, to extinguish, quench;
a. properly: τί, fire or things on fire, Matthew 12:20; Ephesians 6:16; Hebrews 11:34; passive (the Sept. for כָּבָה), to be quenched, to go out: Matthew 25:8; Mark 9:44, 46 (both which vss. T WH omit; Tr brackets), 48.
b. metaphorically, to quench, i. e. to suppress, stifle: τό πνεῦμα, divine influence, 1 Thessalonians 5:19 (ἀγάπην, Song of Solomon 8:7; τά πάθη, 4 Macc. 16:4; χόλον, Homer, Iliad 9, 678; ὕβριν, Plato, legg. 8, 835 d.; τόν θυμόν, ibid. 10, 888 a.).