1. Opposite or Contrary: This meaning is seen in words like "counteract" (to act against), "counterproductive" (working against the desired outcome), and "counterproposal" (an opposing proposal).
2. To Count or Measure: This meaning relates to counting or measuring something, often as a response or in opposition to something else. It's seen in words like "counterfeit" (a fake copy), "counterintelligence" (intelligence gathered to oppose an enemy's intelligence efforts), and "counterbalance" (to balance something by opposing forces).
The specific meaning of "counter" can change depending on the context of the word.
Example:
* Counteract: "The doctor gave her medicine to counteract the effects of the poison." (meaning: to act against)
* Counterfeit: "The police caught the man selling counterfeit money." (meaning: to make a fake copy)
* Counterclockwise: "Turn the knob counterclockwise to open the door." (meaning: opposite of clockwise)