The word 拾人牙慧 is formed by directly combining the characters 拾 (to pick up), 人 (others), and 牙慧 (wisdom from teeth), where 牙慧 metaphorically represents clever remarks or insights. It originates from an ancient anecdote in which the phrase literally described gathering leftover bits from someone's teeth, symbolizing the act of borrowing or plagiarizing others' ideas without original thought, thus constituting a fixed idiom with this meaning.