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early 13c., from Hebrew bel'yya'al "destruction," literally "worthless," from b'li "without" + ya'al "use." Wickedness as an evil force (Deut. xiii:13); later treated as a proper name for Satan (2 Cor. vi:15), though Milton made him one of the fallen angels.
worthlessness, frequently used in the Old Testament as a proper name. It is first used in Deut. 13:13. In the New Testament it is found only in 2 Cor. 6:15, where it is used as a name of Satan, the personification of all that is evil. It is translated "wicked" in Deut. 15:9; Ps. 41:8 (R.V. marg.); 101:3; Prov. 6:12, etc. The expression "son" or "man of Belial" means simply a worthless, lawless person (Judg. 19:22; 20:13; 1 Sam. 1:16; 2:12).
in Judaism and Christianity, the prince of evil spirits and adversary of God.