Translation guide
Describes someone who is slow to understand, stubborn, or insensitive. Japanese has different words for intellectual slowness, stubbornness, and insensitivity.
Describing someone who is intellectually slow or dull.
Means 'slow' or 'dull' in a general sense, including mental slowness. Often used in the phrase 頭の回転が鈍い (slow-witted).
He is slow on the uptake.
Colloquial adjective meaning slow, sluggish, or dim-witted. Often used for someone who is slow to react or understand.
That guy is so thickheaded, explaining is pointless.
Formal or literary term meaning stupid or dull. Stronger and less common in everyday speech.
I'm amazed at his thickheaded attitude.
Describing someone who is obstinate or refuses to change their mind.
Standard word for stubborn or obstinate. Often used for someone who won't listen to reason.
My father is thickheaded and won't listen to my opinion.
Similar to 頑固 but emphasizes obstinacy and being set in one's ways.
Literally 'head is hard', meaning inflexible or stubborn in thinking.
Describing someone who is oblivious to others' feelings or social cues.
鈍い (にぶい) is a general term for slowness or dullness, including mental slowness. 鈍感 (どんかん) specifically refers to insensitivity or being thick-skinned, often about emotions or social awareness.
彼は意固地になって謝らない。
He's being thickheaded and won't apologize.
That person is thickheaded and won't accept new ideas.
He's so thickheaded he says inappropriate things.