brown-nose (v.)youdaoicibaDictYouDict[brown-nose 词源字典]
also brownnose, 1939, American English colloquial, said to be military slang originally, from brown (adj.) + nose (n.), "from the implication that servility is tantamount to having one's nose in the anus of the person from whom advancement is sought" [Webster, 1961]. Related: Brown-noser, brown-nosing (both 1950).[brown-nose etymology, brown-nose origin, 英语词源]