A brutish man. — The Hebrew is apparently from a root meaning “to eat,” and so refers to the man of mere animal nature, who lives for his appetites.
Fool. — From root meaning “fat,” hence “gross,” “stupid.”
In the one case the moral sense has not come into play at all, in the other it is overgrown by sensuality, so that spiritual discernment, insight into the glories of the Divine mind, is impossible.