These characters combine literally to mean “hear one, know ten.” The meaning is very direct: from one piece of information that is heard (or learned), a person can understand ten times (or many times) more, grasping the underlying principles and future implications.
`闻一知十` is a formal and powerful compliment. It's not used casually for everyday cleverness.
A common mistake for English speakers is to use `闻一知十` simply to mean someone learns quickly. It's more profound than that. It's about inference, not speed.
The core of `闻一知十` is the “leap” from “one” to “ten.” It's about connecting the dots that aren't obviously connected. Simply understanding instructions thoroughly, even if done quickly, isn't enough to warrant this compliment.
Avoid using this idiom for trivial matters. Complimenting someone with `闻一知十` for figuring out a simple riddle can sound sarcastic or like you're misusing a powerful phrase. Save it for moments of genuine intellectual brilliance.