南郭 (Nánguō) is a two-character surname that appears in the classical Chinese idiom 滥竽充数, referring to Mr. Nanguo, who pretended to play the flute in a royal ensemble. It is often used as an allusion to someone faking competence.
南郭先生的故事大家都听过吧?
Nánguō xiānsheng de gùshi dàjiā dōu tīng guò ba?
Has everyone heard the story of Mr. Nanguo?
他就像南郭先生一样,根本不会弹琴。
Tā jiù xiàng Nánguō xiānsheng yīyàng, gēnběn bù huì tán qín.
He's just like Mr. Nanguo — he can't play the instrument at all.
别学南郭先生,要靠真本事。
Bié xué Nánguō xiānsheng, yào kào zhēn běnshi.
Don't be like Mr. Nanguo — you need to rely on real ability.