Go from the presence of a foolish man, when thou perceivest not in him the lips of knowledge. When thou perceivest not - the lips of knowledge - Instead of דעת daath, knowledge, several MSS. have שקר sheker, a lie. How this reading came I cannot conjecture. The meaning of the adage is plain: Never associate with a vain, empty fellow, when thou perceivest he can neither convey nor receive instruction.
Related Commentaries of Proverbs 14:7
Proverbs 14:7
7 Go from the presence of a foolish man, when thou perceivest not in him the lips of knowledge.