strong
It's a Chinese idiom. Pinyin is t ó NGD ǎ Ti ě zh ù. It's very reliable and stable. It can also refer to a person's perseverance. It comes from the warning of the world in Ming Dynasty.
Idioms and allusions
Feng Menglong of the Ming Dynasty's the general statement of the police: "more than that, there are many differences in being an official. A local official is a man of iron and bronze. If he withdraws from the office, he dares to say his words."
usage
As an attribute; used in figurative sentences
strong
go to and fro in constant streams - luò yì bù jué
appropriate sth. borrowed for the own use - jiǔ jiǎ bù guī
judge people by outward appearance - yǐ róng qǔ rén