Belial - Vine's Expository Dictionary of New Testament Words
Belial[ 1,,G955, belial ]
is a word frequently used in the Old Testament, with various meanings, especially in the books of Samuel, where it is found nine times. See also Deuteronomy 13:13; Judges 19:22; Judges 20:13; 1 Kings 21:10, 1 Kings 21:13; 2 Chronicles 13:7. Its original meaning was either worthlessness" or "hopeless ruin" (See the RV, margin). It also had the meanings of "extreme wickedness and destruction," the latter indicating the destiny of the former. In the period between the OT and the NT it came to be a proper name for Satan. There may be an indication of this in Nahum 1:15, where the word translated "the wicked one" is Belial.
The oldest form of the word is "Beliar," possibly from a phrase signifying "Lord of the forest," or perhaps simply a corruption of the form "Belial," due to harsh Syriac pronunciation. In the NT, in 2 Corinthians 6:15, it is set in contrast to Christ and represents a personification of the system of impure worship connected especially with the cult of Aphrodite.