A wise man; such as thou seemest and pretendest to be.
Vain knowledge, i.e. empty words, without any sense or solidity in them.
Fill his belly, i.e. satisfy his own mind and conscience, which being secret is compared to the inwards of the belly; as Job_32:19Pro_20:27 22:18.
With the east wind, i.e. with discourses which are not only flashy and unprofitable, and without any weight, but also boisterous and pernicious, both to himself and others; as the east wind was in those parts, Gen_41:6Exo_10:13Hos_12:1.