Why is the ninth month called September?
1871, of West African origin (cf. Kikongo zumbi "fetish;" Kimbundu nzambi "god"), originally the name of a snake god, later with meaning "reanimated corpse" in voodoo cult. But perhaps also from Louisiana creole word meaning "phantom, ghost," from Spanish sombra "shade, ghost." Sense "slow-witted person" is recorded from 1936.
[origin uncertain; perhaps fr an African word akin to nzambi, ''god''; perhaps fr Louisiana Creole, ''phantom, ghost,'' fr Spanish sombra, ''shade, ghost''; popularized by horror stories and movies featuring the walking dead persons of voodoo belief]