Definition & Meaning of "brown noser"in English

What is the origin of the term "brown noser" and how is it used?

Brown noser is a slang term that appeared in mid-20th-century English to describe a person who seeks favor through excessive flattery or servile behavior. The term comes from the literal idea of having one's nose so close to someone's butt that it becomes metaphorically "brown," emphasizing extreme submission or obsequiousness. Literally, it labels someone as overly eager to please or ingratiate themselves. Historically, it was derogatory, used to mock or criticize sycophantic behavior, and today it remains informal and insulting, typically used in workplaces, schools, or casual conversation rather than polite or neutral contexts.