Acid is from the Latin adjective acidus, meaning sharp, sour. It has the same root as acer keen, sharp. Even in Latin acid(us) had both modern meaning: sour-tasting and sour in temperament, disagreeable. From acid come words such as acidify and acidity.
Acrid also uses the Latin suffix -id, meaning with a particular quality. Acrid is used mainly to describe smells and tastes: acrid smoke.
Acerbic comments are harsh, bitter, and cutting. They might be made during an acrimonious dispute one full of bitterness and acrimony.
Acute comes from a Latin word meaning sharpened or coming to a sharp point. So an acute angle is one that is less than 90 degrees. Hence the word came to mean reaching a crisis, critical and also intense, to the point. We speak of a problem as becoming acute; of a toothache as giving us acute pain; or of a person as having an acute mind or being acutely aware of something.
Acuity is sharpness of mind and quickness of understanding. Acumen too, though it is usually a long-term quality, like shrewdness.
Acupuncture is the sharp puncturing of the skin with needles.
For Scientific english editing and Medical Writing Services visit www.manuscriptedit.com