The purpose of using a counterargument is to anticipate a reader or opponent´s concerns and rebuff them to show that they are false.
This refers to the use of argument and logic to anticipate and counter an argument of an opponent.
Please note that your question is incomplete so I gave you a general overview so that you could get a better understanding of the concept.
Read more about counterarguments here:
https://brainly.com/question/10613624