Back-scratching is a term that refers to the act of mutual praise or favoritism between two parties. It's often associated with lack of impartiality and unethical behavior in professional contexts. However, there are several other similar expressions that can be used to describe this phenomenon. Some of these synonyms include "mutual admiration," "reciprocal goodwill," "logrolling," "tit for tat," or "you scratch my back, and I'll scratch yours." These terms are commonly used in political circles, but they can also apply to any other social or professional context where people seek to gain favors or influence through flattery and collusion.