Meaning:
Literally meaning “the second knife,” this idiom refers to people who are not very skillful at their jobs. It originated from the trade of plasterers. It’s said that traditionally Chinese plasterers would sell carved turnips in winter when there were not many building jobs in the market. Since they were not specialized in turnip carving — a chef’s job, they were called “the second knife.” Some people also say that the best plasterers were called the “first knife” while those not as good were “second knives.”
Example:
A: 我家的水龙头漏水，让小明来修修吧?
Wǒ jiā de shuǐlóngtóu lòushuǐ, ràng xiǎomíng lái xīuxīu ba?
My tap is leaking. How about asking Xiao Ming to come over and have it fixed?
B: 你最好还是找专业的水管工来修，他不过是二把刀。
Nǐ zuìhǎo hái shì zhǎo zhuānyè de shuǐguǎngōng lái xīu, tā bùguò shì èrbádāo。
You’d better call for a real plumber. He’s not professional.
(First editor: Debra Li)