NMIL is often used as an acronym for "narcissistic mother-in-law," referring to a difficult relationship with a spouse's mother who displays narcissistic behavior. However, there are a variety of synonyms that can be used to describe this type of person, such as a controlling parent, critical mother-in-law, or intrusive mother figure. Other terms commonly used to describe a toxic parent may include overbearing, demanding, or manipulative. Regardless of the specific designation, the term typically indicates a strained and complicated relationship, and it can be valuable to understand the motivations and behaviors of a difficult family member in order to maintain healthy boundaries and relationships with loved ones.