Answer:
An author's counterargument is an argument that contradicts and argues against the author's claim.
Step-by-step explanation:
An author's claim usually has several supporting points stated in the thesis, where the points are usually supported and proven in the following paragraphs. Then a counterargument is sometimes used to contradict the claim. This is usually used to give a second point of view, which is then refuted later, leading to the conclusion.