Belial
Easton's Dictionary
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).
Smith's Dictionary
The meaning of this word as found in the Scriptures is worthlessness, and hence reckless, lawlessness. The expression son or man of Belial must be understood as meaning simply a worthless, lawless fellow. The term as used in (2 Corinthians 6:15) is generally understood as an appellative of Satan, as the personification of all that was bad.