The term 'PERSON AUTHORIZED TO ACT FOR ANOTHER' can be summarized as a 'PROXY' (5 letters). A PROXY is an individual who is authorized to act on behalf of another person or entity. This type of authorization is often used in business and legal contexts, where a PROXY is appointed to represent the interests of another party. In some cases, a PROXY may be given the power to make decisions on behalf of the other party, while in other cases, the PROXY may only be able to cast votes or provide advice.