Describes a person or their thinking as slow, lacking sharpness, or unintelligent. Often used critically or self-deprecatingly. Not a casual slang term; carries a somewhat formal or literary tone.
He has a dull-looking face, but he's actually very sharp.
I'm ashamed of myself for making such a stupid mistake.
愚鈍 means dull-witted or foolish, the direct opposite of the sharp, brilliant intelligence praised by 英明.
愚鈍 describes a slow, dull-witted mind, contrasting with 鋭敏's sharp-witted, astute intellect.
Compound of 愚 (foolish, stupid) and 鈍 (dull, slow). The exact historical derivation is uncertain, but the combination directly conveys the meaning of mental dullness.