The phrase "other man" refers to a male who is not the primary romantic partner in a relationship. There are several synonyms for this term, including "lover", "paramour", "mistress", "adulterer", and "affair partner". The use of these terms can vary depending on the context and the tone of the conversation. While some of these synonyms may have negative connotations, others can be more neutral or even positive in certain situations. Ultimately, it is important to choose the appropriate term based on the situation and the desired effect of the communication.