From tsel and maveth; shade of death, i.e. The grave (figuratively, calamity) -- shadow of death.
see HEBREW tsel
see HEBREW maveth
H6757. tsalmaveth
צַלְמָ֫וֶת noun [masculine] death-shadow, deep shadow, in poetry (probably = צֵל + ᵐ5 מָוֶת,. (usually) σκιὰ θανάτου, compare ᵑ9 ᵑ6, so Thes SchwLeben n. d. Tode, 194, see especially NöZAW xvii (1897), 183 ff.; Ew Br and most modern (after older commentaries) read צַלְמוּת darkness, deep darkness, compare Arabic IV, Assyrian [ƒalâmu], Ethiopic be black, dark); **compare darkness; WeKl. Proph. ed. 3, 81 would read feminine plural צְלָמוֺת, like Qor 2:16; 2:18; and frequently. — death-shadow, often "" לַיְלָה חשֶׁךְ, etc., and opposed to אוֺר בֹּקֶר,.
1 = deep shadow, darkness (compare אֵל אַרְזֵי אֵל, הַרְרֵי): Amos 5:8; Job 3:5; 12:22; 24:17a 28:3; 34:22; of eyes heavy with weeping 16:16; צ ׳בַּלְהוֺת24:17b terrors of the darkness.
2 figurative
a. of distress Jeremiah 13:16; Psalm 107:10; 107:14; צ ׳אֶרֶץ Isaiah 9:1.
b. of extreme danger Jeremiah 2:6; Psalm 23:4; 44:20.
3 characterizing world of the dead, וצ חשֶׁךְ ׳אֶרֶץ Job 10:21, צ אֹפֶל ׳כְּמוֺ 10:22 (text dubious, see Bu Du); צ ׳וְשַׁעֲרֵי 38:17 (ᵐ5 πυλωροὶ δὲ ᾅδου; "" שַׁעֲרֵימָֿ֑וֶת).