Kiss-up is a slang term that refers to someone who flatters or tries to please others in order to gain advantage or favor. This term also has synonyms such as bootlicker, brown-noser, apple-polisher, sycophant, toady and ass-kisser. These terms describe individuals who often seek personal gain through insincere compliments and false admiration towards people in positions of power. These individuals are often viewed negatively and may be seen as manipulative or disingenuous. It is important to note that building genuine relationships based on trust and mutual respect is more effective than indulging in such behavior.