The word 拍马屁 is formed by combining three characters: 拍, meaning "to pat", 马, meaning "horse", and 屁, meaning "buttocks". Literally, the phrase translates to "pat the horse's butt", originating from the practice of grooms stroking horses' hindquarters to appease or impress their owners, which evolved into a metaphorical idiom for insincere flattery aimed at gaining favor.