A person who constantly tries to ingratiate themselves with others in a negative way is often referred to as an "ass kisser." While this term is widely used, it's important to remember that it can be derogatory and offensive. In a professional setting, using more appropriate synonyms can help communicate the same message without resorting to crude language. Some examples of synonyms for "ass kisser" include flatterer, sycophant, brown-noser, toady, flunky, and yes-man. Each of these terms describes someone who seeks favor and approval from those in power by excessively praising and agreeing with them. While it's important to be respectful and polite, it's also crucial to be authentic and true to oneself.