The Forsaken names are all nicknames to ridicule them or out of contempt (except for Lanfear, who chose her name).

Maybe the encyclopedia will contain all literal translations. We know that Moghedien was the name of a tiny, little spider from the AoL, that Cyndane means "Last Chance" and that Be'lal means "the Envious". Probably Graendal means something like "the Decadent or the Lustful" and Semirhage something like "the Sadist or the Torturer". Maybe Aginor means something like "the Butcher", because of his excessive experiments with humans, Rahvin "the Lecher" and Demandred perhaps "Full of Hate". No good idea yet on Balthamel (maybe the Drunkard?), Mesaana (maybe something related to children like bugbear) and Asmodean (maybe something like "Blood Harp" ).