1. Having a sharp point or tip.
2. Keenly perceptive or discerning: "a raw, chilling and psychologically acute novel of human passions reduced to their deadliest essence" (Literary Guild Magazine). See synonyms at sharp.
3. Reacting readily to stimuli or impressions; sensitive: His hearing was unusually acute.
4. Of great importance or consequence; crucial: an acute lack of research funds.
5. Extremely sharp or severe; intense: acute pain; acute relief.
6. Medicine.
   1. Having a rapid onset and following a short but severe course: acute disease.
   2. Afflicted by a disease exhibiting a rapid onset followed by a short, severe course: acute patients.
7. Music. High in pitch; shrill.
8. Geometry. Having an acute angle: an acute triangle.

[Latin acūtus, past participle of acuere, to sharpen, from acus, needle.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.