"Opposing counsel" refers to the lawyer or legal team that represents the other side in a legal case or dispute. They are responsible for advocating for the opposing party's interests and presenting arguments against your side. Full definition
Try to come to an agreement with opposing counsel on as many disputed terms as possible. (a2lc.com)
Finding the top worst types of opposing lawyers has taken me 7 years of litigation, over 300 court hearings and hundreds of opposing counsel dealt with. (ylaw.ca)
That would entail a set of documents all of which were brought up by opposing counsel in deposition. (radicalconcepts.com)