ob·tuse (ŏb-ts, -tys, əb-)
adj. ob·tus·er, ob·tus·est
a. Lacking quickness of perception or intellect.
b. Characterized by a lack of intelligence or sensitivity: an obtuse remark.
c. Not distinctly felt: an obtuse pain.
a. Not sharp, pointed, or acute in form; blunt.
b. Having an obtuse angle: an obtuse triangle.
c. Botany Having a blunt or rounded tip: an obtuse leaf.
[Middle English, from Old French, from Latin obtūsus, past participle of obtundere, to blunt; see OBTUND.]
Usage Note: Obtuse is sometimes used where one might expect abstruse instead, but the Usage Panel is divided on the acceptability of these usages. In our 2009 survey, 55 percent of the Usage Panel rejected obtuse meaning "recondite," as in The reader has to struggle through dense prose and obtuse references to modern philosophers. Some 52 percent rejected the word when used to mean "indirect or oblique" in the sentence Divorce is mentioned, and there are a few obtuse references to sex. By contrast, 56 percent accepted sentences in which obtuse was used to mean "hard to follow or understand" in the phrases obtuse instructions and obtuse explanation. Perhaps the use of the word as a sophisticated synonym of stupid makes these extended derogatory uses more tolerable than they otherwise might be.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.