The word "不准" is formed through a direct and logical conceptual combination of its two component characters: "不", which conveys negation meaning "not" or "no", and "准", which carries the core meaning of "to permit" or "to allow". By placing the negation directly before the concept of permission, the compound naturally and intuitively creates the single idea of "not to permit", resulting in the meaning "to forbid" or "prohibited". It is a straightforward semantic fusion where the first character modifies and reverses the meaning of the second.