necro-

From Ancient Greek νεκρός (nekrós, “dead body”), from the Proto-Indo-European suffixed full-grade *nekro- of *neḱ- (“perish, disappear”); see also Middle Welsh angheu (“death”), Breton ankou, Old Irish éc, Latin noxius (“harmful”), nocēo (“to hurt, harm”), nex (“murder, violent death”) (as opposed to mors), Old Persian 𐎻𐎴𐎰𐎹𐎫𐎹 (vi-n-θ-y-t-y /vi-nathayatiy/, “he injures”), Avestan 𐬥𐬀𐬯𐬌𐬌𐬈𐬌𐬙𐬌 (nasiieⁱti, “disappears”), 𐬥𐬀𐬯𐬎- (nasu-, “corpse”), Sanskrit नश्यति (naśyati, “disappear, perish”). By surface analysis, necr- + -o-.

来源：wiktionary