surreptitious
The Chinese idiom is sh é NGU ǐ n á NC è, which means no one can guess. From the romance of the Three Kingdoms by Luo Guanzhong of Ming Dynasty.
Idiom explanation
Measurement: conjecture. It's very mysterious, and it's hard to measure. No one can guess.
The origin of Idioms
Chapter 87 of the romance of the Three Kingdoms by Luo Guanzhong of the Ming Dynasty: "all generals prostrate themselves and say," the prime minister is unpredictable. "
Idiom usage
As a predicate, attribute, etc
Examples
It's hard to know what the dragon is. The fourth part of Ming Dynasty's Wumingshi's "attacking Jin and prospering Qi"
Analysis of Idioms
[synonym]: uncanny, uncanny
surreptitious