An ungodly (worthless) witness scorneth judgment; derides the Law which denounces perjury and compels a witness to speak truth (Exodus 20:16; Le Exodus 5:1), and, as is implied he bears false testimony, thus proving himself "a witness of Belial," according to the Hebrew term.
Septuagint, "He who becometh security for a foolish child outrages judgment." The mouth of the wicked devoureth iniquity; swallows it eagerly as a toothsome morsel (Proverbs 18:8). So we have in Job 15:16,"A man that drinketh iniquity like water" (see on Proverbs 26:6).
Such a man will lie and slander with the utmost pleasure, living and battening on wickedness. Septuagint, "The mouth of the impious drinketh judgments ( κρίσεις)," i.e. boldly transgresses the Law.