And also, when the fool walks along the road, his understanding fails him
and he says to everyone that he is a fool. Bible other translations

“understanding fails him.” Literally, “his heart is missing (or “lacking”). [For more on “heart” and its use of “understanding” or “good sense,” see commentary on Prov. 15:21].

“fool.” The Hebrew word for “fool” is sakal (#05530 סָכָל), which is a quite rare word for “fool” and occurs only in Ecclesiastes and Jeremiah (Ecc. 7:17; 10:3, 6, 14; Jer. 4:22; 5:21), and not at all in Psalms or Proverbs.

“and he says.” The fool shows by his words and actions that he is a fool. His actions are “speaking.” The Bible has quite a bit to say about how fools behave (cp. Prov. 12:16, 23; 13:16; 14:3, 16; 15:2; 18:6, 7; 29:11), but Proverbs does not use this particular word for “fool.”

Commentary for: Ecclesiastes 10:3