Easton's Bible Dictionary (1897)
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. V. ); 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 Bible Dictionary (1863)
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.
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
BE'LIAL (worthlessness). This word is applied by the sacred writers to such lewd, profligate, and vile persons as seem to regard neither God nor man. Deut 13:13; Jud 19:22, and 1 Sam 2:12. Hence the question of the apostle, 2 Cor 6:15, to the citizens of Corinth, which was remarkable for its lewdness and profligacy, has great force: "What concord hath Christ with Belial," the prince of licentiousness and corruption?
Hitchcock's Bible Names (1869)
wicked, worthless