Acute

1. Having nice discernment; perceiving or using minute distinctions; penetrating; clever; shrewd; -- opposed to dull or stupid; as, an acute observer; acute remarks, or reasoning.
2. Attended with symptoms of some degree of severity, and coming speedily to a crisis; -- opposed to chronic; as, an acute disease.
3. Sharp at the end; ending in a sharp point; pointed; -- opposed to blunt or obtuse; as, an acute angle; an acute leaf.
4. To give an acute sound to; as, he acutes his rising inflection too much.
5. Having nice or quick sensibility; susceptible to slight impressions; acting keenly on the senses; sharp; keen; intense; as, a man of acute eyesight, hearing, or feeling; acute pain or pleasure.
6. High, or shrill, in respect to some other sound; -- opposed to grave or low; as, an acute tone or accent.