nahash; as a noun, nahash translates as snake, and as a verb it literally translates as hissing. The verb form can be extended to mean whispering, so it has historically been understood to refer to enchantment.
onan; onan literally translates as clouds, possibly referring to nephomancy. Some translations take this as an allusion to bird flocks, and therefore translate it as augury.
kashaph; kashaph is of ambiguous meaning, being either from a root meaning mutter, or from a compound of the words kash (herb) and hapalah (using) - hence meaning herb user. The Septuagint renders the same phrase as pharmakia (poison), so it may refer to magic potions
being a ba'al ob; ba'al ob literally means master of spirits. The corresponding parts of the Septuagint refer to eggastrimuthos (gastromancy), a form of necromantic ventriloquism, in which the voice seems to be located in the stomach.
being a yidde'oni; yidde'oni literally means gainer of information from ghosts
being a doresh el ha-metim; doresh el ha-metim literally means (one who) questions corpses
qasam qesem; qasam qesem literally means distributes distributions, possibly referring to cleromancy
khabar kheber; khabar kheber literally means join joinings, possibly referring to charms
The exact difference between the three forbidden forms of necromancy is a matter of uncertainty; yidde'oni is usually only mentioned together with ba'al ob, and its semantic similarity to doresh el ha-metim raises the question of why all three are mentioned in the same verse of Deuteronomy. Classical Jewish sources argued that yidde'oni might be another form of ventriloquism, in which the voice is cast into at a bone which is placed into the ventriloquist's mouth. Rashi describes the doresh el ha-metim as a person who would sleep in cemeteries, after having starved themselves, in order to become possessed. The Witch of Endor was a ba'al ob; the Septuagint again renders this as eggastrimuthos, thus describing her as a (necromantic) ventriloquist, although (one who has) familiar spirits is the more common English translation.
Like the law code of Hammurabi, the Torah assigns the death penalty to practitioners of certain forms of witchcraft/divination; the Holiness Code of Leviticus ascribes the death penalty for two of the three necromantic practices, namely Ba'al ob and Yidde'oni, while the Covenant Code of Exodus ascribes it for kashaph. The Torah's forbiddence of forms of divination does not appear to universally reflect historic Israelite attitudes; scholars think that teraphim were ancestral skulls, possibly used for necromantic divination, and the bible is clear that Urim and Thummim, associated with the Ephod, were used for some form of divination, thought by scholars to be cleromancy.