المعنى الاصطلاحي :

Having the authority to do a particular action on behalf of another so that the outcome of the action would benefit the represented person.

الشرح المختصر :

"Niyābah" (representation) is the act of saying or doing something on behalf of someone else, whether this representation relates to the rights of Allah or the rights of humans. "Niyābah" is of two types: 1. Agreed-upon "niyābah", which is the power of attorney. 2. Legal "niyābah", which is guardianship. This is when certain people become legally responsible for overseeing the affairs of those who are unable to make their own decisions due to young age or similar conditions.

التعريف اللغوي المختصر :

"Niyābah": representation, acting on behalf of others. Derived from "nawb", which means going back one time after another. "Tanāwub": alternation.