lips. Put by Figure of speech Metonymy (of Cause), App-6, for what is spoken by them.
understanding. Hebrew "heart", put by Figure of speech Metonymy (of Subject), App-6, for understanding.
foolish. Same word as in Proverbs 10:8.
Related Commentaries of Proverbs 10:13
Proverbs 10:13
13 In the lips of him that hath understanding wisdom is found: but a rod is for the back of him that is void of understanding.d