Định Nghĩa và Ý Nghĩa của "out of {one's} depth"

What is the origin of the idiom "out of one's depth" and when to use it?

The idiom "out of one's depth" has its origins in nautical terminology. It draws from the idea of a person swimming or floating in water that is deeper than their own height, making it difficult for them to touch the bottom or stay afloat. This expression is used to describe a situation in which someone lacks the necessary skills, knowledge, or experience to cope with or understand what is happening.