Acute

acute stems from a Latin word meaning "to sharpen". Acute means "sharp" or "coming to a sharp point" and thus it has also come to mean "reaching a crisis; critical; keen; intense; violent". Note carefully these various meanings in the following sentences:
An acute angle is an angle of less than 90 degrees.
He is suffering from an acute appendicitis.
The food shortage in India is becoming acute.
The boy has a quick, acute mind.
His toothache was causing acute pain.
A word based on acute is acutely, meaning "intensely; extremely; keenly; highly".
He was acutely conscious of their disapproval.

Root: Acu-, Acr-

The Latin root acu- or acr- means "sharp". You should sharpen your vocabulary with the five core words in which the root acu- or acr- appear: acrid, acrimony, acuity, acumen, acute.