עֲטֶ֣רֶת חֲכָמִ֣ים עָשְׁרָ֑ם אִוֶּ֖לֶת כְּסִילִ֣ים אִוֶּֽלֶת׃
智慧人的冠冕是他們的財富;愚昧人的愚妄,仍是愚妄。
Rashi
the folly of the foolish is folly The ruin of the fools is the folly that they neglected to learn wisdom.
Malbim
It can also be explained: The wealth of the sages is their crown. That is to say, [their crown is] that which they, through their wisdom, separate from the desires of the world and are happy with their portion, since that is true wealth — one who does not desire [anything], such that he does not lack anything. For the wealthy person who is desirous and his eye will never be satiated (alluding to Ecclesiastes 4:8), he is truly the poor one.