愚昧 (yú mèi) is an adjective meaning 'ignorant' or 'unenlightened', often implying a lack of education, critical thinking, or awareness—especially in matters of science, reason, or social progress. The first character 愚 (yú) means 'foolish' or 'stupid', while 昧 (mèi) means 'obscure', 'dark', or 'unaware'; together, they evoke the image of mental darkness or intellectual blindness. It carries a strong negative connotation and is frequently used in formal or critical discourse—not for light-hearted teasing but to describe harmful or outdated beliefs.

This word appears commonly in essays, news reports, and historical commentary, especially when criticizing superstition, prejudice, or resistance to modern knowledge. It’s not used for simple lack of information (e.g., not knowing a phone number), but rather for deep-seated, uncritical adherence to false or harmful ideas—like rejecting vaccines due to misinformation or upholding discriminatory traditions without reflection.