KanjiJLPT N1
Foolish

foolish, folly, absurdity, stupid

Mnemonic

A monkey who lets its heart guide every impulse—grabbing shiny objects, poking beehives, trusting every snake—is the most foolish creature in the jungle. It never pauses to think, just feels and leaps, and the other animals shake their heads at such foolish antics.
Additional thoughts
Visualize a monkey clutching its chest (heart) dramatically while doing something spectacularly stupid, like juggling scorpions. Heart overriding brain equals pure foolishness.
Quick recall
A monkey ruled by raw heart acts completely foolish.

Details

The keyword for 愚 is foolish. This kanji conveys the sense of stupidity, ignorance, or lack of wisdom and good judgment. It refers to someone who acts without thinking or who lacks the intellectual capacity to make sound decisions. The character is often used to express self-deprecation in formal Japanese, where one humbly refers to oneself or one's opinions as foolish as a matter of politeness.
On'yomi
Kun'yomi
おろ.か

Used in vocab