Latin root ac, acr, acu means keen, sharp, unpleasantly bitter
e.g - acrid, acrimony, acuity, acute, acerbic, acumen, acupuncture.
Acrid - having sharp quality in smells and taste; bitter or burning to the senses; bitter in temper or manner
An acrid dispute
Acrid fumes from burning rubber
Acrimony - sharpness of speech or temper; bitterness of manner or words
The dispute was settled without acrimony
Acuity - sharpness of mind, thought, vision or hearing; quick in understanding
The teacher has great mental acuity
Acumen - sharpness of mind; intelligence; ability to take good decisions; shrewdness.
Display great political acumen
Acid - sharp; sour
Vinegar has an acid taste.
Acerbic - sharp and harsh
An acerbic remark
Online link to Root Words Suffix Prefix