Why is Zimah like laughing for a Kesil?
Rashi: It is [Zenus,] the counsel of sinners.
R. Yonah: Zimah is intent. Just like jesting comes easily from thought, for it comes often without intent, so the action comes easily from the intent of a fool. His way is to do all that he plots. He does not distinguish between desire that crosses his spirit, without investigation, and intent that is carried out.
Malbim: Kesil is estranged from the ways of Chachmah, due to the Yetzer of his heart and his desires. According to how his heart rules - in the ways of Chachmah or folly - so will be his nature. His deeds are not attributed to his choice, rather, to habit and second nature. A fool does Zimah without thought, Da'as or preparation, like he laughs (if something funny occurs) by necessity, without thought or choice.
What does the verse say about Chachmah?
Rashi: In the eyes of Ish Tevunah, it is easy to do, like jesting.
R. Yonah: For an Ish Tevunah, Chachmah is doing his intent. The primary Chachmah is at the time of deed. He investigates greatly until he completes (decides properly).
Malbim: Ish Tevunah is one who gathered all matters of Binah in his Nefesh (this distinguishes Tevunah from Binah). Then Chachmah is from the lips and outwards for it is fluent on his lips; he need not think at all, like I explained (refer to 10:13:1:3). Conduct according to Chachmah is via habit, by itself, just like laughing comes by itself naturally.
