Satan

proper name of the supreme evil spirit in Christianity, Old English Satan, from Late Latin Satan (in Vulgate in Old Testament only), from Greek Satanas, from Hebrew satan "adversary, one who plots against another," from satan "to show enmity to, oppose, plot against," from root s-t-n "one who opposes, obstructs, or acts as an adversary."

In Septuagint (Greek) usually translated as diabolos "slanderer," literally "one who throws (something) across" the path of another (see devil (n.)), though epiboulos "plotter" is used once.

In biblical sources the Hebrew term the satan describes an adversarial role. It is not the name of a particular character. Although Hebrew storytellers as early as the sixth century B.C.E. occasionally introduced a supernatural character whom they called the satan, what they meant was any one of the angels sent by God for the specific purpose of blocking or obstructing human activity. [Elaine Pagels, "The Origin of Satan," 1995]

The devil. In the Bible (see also Bible), Satan is identified with the tempter who encourages the fall of Adam and Eve; he is the accuser who torments Job in the hope that he will curse God; the one who offers Jesus all the kingdoms of the world if Jesus will worship him (see Get thee behind me, Satan); and the evil one who puts betrayal in the heart of Judas. Satan will one day be confined in hell, but until then he is free to roam the Earth.