From cakal; silly -- fool(-ish), sottish.
see HEBREW cakal
H5530. sakal
סָכָל noun masculine fool (on formation compare LagBN 48): — Jeremiah 5:21; Ecclesiastes 2:19; 7:17; 10:3 (twice in verse); 10:14; plural adjective סְכָלִים Jeremiah 4:22.