على وجه يصح
In an admissible or appropriate manner.
This condition establishes the need for an ʿalāqah, a meaningful connection between the assigned and intended senses. A random incorrect label does not become rhetorical figurative use merely because the original designation no longer fits.
Using “lion” for a brave person can exploit resemblance in courage. Calling a book a “horse” with no intelligible relation or context does not thereby create a valid rhetorical transfer.