Translation guide
The English word "obtuse" has several distinct meanings: describing an angle greater than 90°, a slow-witted person, an insensitive remark, or a dull shape. This guide covers natural Japanese equivalents for each sense.
Describing an angle between 90 and 180 degrees.
The standard mathematical term for an obtuse angle.
This triangle contains an obtuse angle.
Describing a person who is slow to understand or lacking intelligence.
Means 'dull' or 'slow' mentally. Often used for someone who is not quick on the uptake.
He is slow on the uptake.
She is obtuse, so it takes time to explain things.
Literally 'insensitive', often used for someone who is thick-skinned or slow to catch on to social cues.
Idiomatic phrase meaning 'slow to understand' or 'poor at grasping things'.
A literary or formal term meaning 'stupid' or 'obtuse'. Rare in everyday speech.
Describing a comment or action that is annoyingly insensitive or lacking in perception.
Used for a person or remark that is insensitive to others' feelings.
I was hurt by his obtuse remark.
Literally 'can't read the air', meaning someone who is oblivious to social atmosphere and makes tactless comments.
Means 'insensitive' or 'thoughtless', often used for remarks that lack consideration.
Describing an object that is not sharp or pointed; dull-edged.
While 鈍い (にぶい) is the closest equivalent, it can sound harsh if used directly to describe someone. In polite conversation, consider softer phrases like 少し理解が遅い (すこしりかいがおそい, a bit slow to understand) or 飲み込みが悪い (のみこみがわるい).
Both mean 'insensitive', but 鈍感 (どんかん) implies a lack of perception or awareness, while 無神経 (むしんけい) suggests a lack of consideration or thoughtlessness. For an obtuse remark, 無神経 is often more appropriate when the speaker should have known better.
彼は鈍感で、冗談が通じない。
He is obtuse and doesn't get jokes.
He is obtuse, so I have to explain things many times.
I am amazed at his obtuse behavior.
He is obtuse and always says inappropriate things.
そんな無神経なことを言うなんて信じられない。
I can't believe you would say such an obtuse thing.