Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Scrabble
  • Spanish Central
  • Learner's Dictionary


adjective, ob·tuse \äb-ˈtüs, əb-, -ˈtyüs\

Simple Definition of obtuse

  • : stupid or unintelligent : not able to think clearly or to understand what is obvious or simple

  • mathematics : not ending in a sharp point : measuring between 90 degrees and 180 degrees

Source: Merriam-Webster's Learner's Dictionary

Full Definition of obtuse


  1. 1 a :  not pointed or acute :  blunt b (1) of an angle :  exceeding 90 degrees but less than 180 degrees (2) :  having an obtuse angle <an obtuse triangle> — see triangle illustration c of a leaf :  rounded at the free end

  2. 2 a :  lacking sharpness or quickness of sensibility or intellect :  insensitive, stupid b :  difficult to comprehend :  not clear or precise in thought or expression

obtusely adverb
obtuseness noun

Examples of obtuse in a sentence

  1. Murdoch's art, like all good art, is highly structured and controlled—a house neat and clean enough to satisfy the most morally obtuse of her upper-class British characters. —Martha C. Nussbaum, New Republic, 31 Dec. 2001 & 7 Jan. 2002

  2. Only the most obtuse missed the main message: humans risked so distorting the natural order that they were sentencing themselves to be destroyed by frost or furnace. —Joseph A. Amato, Dust, 2000

  3. In fact, he was too obtuse even to realize that his assignment to Tejas was a demotion … —James A. Michener, Texas, 1985

  4. … either he, and the other people in his shop, and two people I subsequently ask are incapable of giving directions, or I am too rattled and obtuse to follow them, but I cannot find the police station. —Renata Adler, Pitch Dark, 1983

  5. He is too obtuse to take a hint.

  6. <obtuse scissors designed so that young users will not cut themselves>

Did You Know?

Obtuse, which comes to us from the Latin word obtusus, meaning "dull" or "blunt," can describe an angle that is not acute or a person who has a "dull" or insensitive mind. The word has also developed a somewhat controversial third sense of "hard to comprehend," probably as a result of confusion with "abstruse." It is now possible to speak of "obtuse language" and "obtuse explanations," as well as "obtuse angles" and "obtuse readers." This sense of "obtuse" is well established, but it may attract some criticism. If you're hesitant about using new meanings of words, you should probably stick with "abstruse" when you want a word meaning "difficult to understand."

Origin of obtuse

Middle English, from Latin obtusus blunt, dull, from past participle of obtundere to beat against, blunt, from ob- against + tundere to beat — more at ob-, contusion

First Known Use: 15th century

Synonym Discussion of obtuse

dull, blunt, obtuse mean not sharp, keen, or acute. dull suggests a lack or loss of keenness, zest, or pungency <a dull pain> <a dull mind>. blunt suggests an inherent lack of sharpness or quickness of feeling or perception <a person of blunt sensibility>. obtuse implies such bluntness as makes one insensitive in perception or imagination <too obtuse to take the hint>.

Other Mathematics and Statistics Terms

OBTUSE Defined for Kids


adjective ob·tuse \äb-ˈtüs, -ˈtyüs\

Definition of obtuse for Students

  1. 1 :  measuring more than a right angle

  2. 2 :  not able to understand something obvious

Medical Dictionary


adjective ob·tuse \äb-ˈt(y)üs, əb-\

Medical Definition of obtuse

obtuser; est

  1. 1:  lacking sharpness or quickness of sensibility or intellect

  2. 2:  not pointed or acute <obtuse pain>

Seen and Heard

What made you want to look up obtuse? Please tell us where you read or heard it (including the quote, if possible).


the range of perception or understanding

Get Word of the Day daily email!


Take a 3-minute break and test your skills!


Which of these is a synonym of nonplus?

disapprove perplex reduce soothe
Name That Thing

Test your visual vocabulary with our 10-question challenge!


Test Your Knowledge - and learn some interesting things along the way.