What does obtuse mean?
Obtuse has a precise mathematical meaning and a familiar figurative one. In geometry, an obtuse angle measures more than 90 degrees but less than 180 degrees, making it wider than a right angle; an obtuse triangle contains one such angle. In everyday English, the word describes someone who is slow to understand, has limited insight, or fails to notice what others recognize. This figurative use can sound blunt or slightly insulting, so it is often softened in tone depending on context. The word also has a less common descriptive use for dull or indistinct sound. Derived from a Latin term meaning “blunted,” obtuse effectively conveys the idea of a sharp point that has been made less precise, whether the subject is an angle, a sound, or a person's understanding. Its usefulness lies in this combination of mathematical precision and a vivid figurative contrast with acuity, sharpness, and alertness.
adjectiveObtuse describes an angle greater than 90 degrees and less than 180 degrees. Figuratively, it means slow to understand, unintelligent, or insensitive.
- An angle measuring more than 90 degrees and less than 180 degrees.
- A person who is slow to understand, unintelligent, or insensitive.
- A sound that is dull, muffled, or indistinct.
"His obtuse explanation left the audience more confused than before."
"The triangle has one obtuse angle and two acute angles."
"Rather than calling him obtuse, she explained the difficult idea in a different way."
From the Latin for “blunted,” obtuse names an angle wider than a right angle—and a mind that hasn't quite caught on.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does obtuse come from?
The English word comes from Latin obtusus, “blunted” or “dull,” a past participle of obtundere, “to blunt.” The Latin root combines ob-, meaning “against” or “in front of,” with tundere, “to beat.” The same root underlies English words such as obtund and obtundate, which refer to making something blunt, dull, or less sensitive.
Related word forms
How obtuse is actually used
In figurative use, obtuse can describe a person's slow reasoning or lack of sensitivity and may sound mildly insulting. In geometry, it is a precise, neutral technical term.