How is his heart lacking?
Rav Sadya Gaon: His Da'as is lacking.
Rashbam: He is astounded and crazed.
Ri Kara: He has all the limbs, and lacks only a heart - "Lamah Zeh Mechir b'Yad Kesil Liknos Chachmah v'Lev Ayin" (Mishlei 17:16).
Seforno: He goes to get something improper, due to overpowering of his desire, and uses improper ways to get it.
Why does it say "[v'Gam ba'Derech
Rav Sadya Gaon: It is as if he announces his folly to everyone.
Rashi: Via his going and speech, all recognize that he is a lunatic.
Ibn Ezra, Rashbam: In all his matters and words, his lack of intellect and Da'as is seen, even when he goes on the road. It is as if he verbally tells all that he is a fool. Ri Kara - surely he does not overtly say that he is a fool!
Rid: Also the way he walks publicizes his folly, that he lacks a heart. It is unlike the way others walk.
Seforno: Via using improper means, many stand against him to thwart his intent, like the matter of Achashverosh 1 .
Metzudas David: Even when he is on the road, and not in his house; even when he goes, and does not delay - his deeds and affairs are not with intellect. It is as if he says that he is a fool.
I.e. he appointed overseers to gather many girls and he work have relations with all of them, but only one will become queen, so people hid their daughters (Megilah 12b). (PF).
