In personal finance, fiduciary can be used as either a noun or as an adjective. As a noun, the term represents an individual acting as the agent of a company, with a special relation of trust and responsibility. For example, you might say "I was offered this great deal by the company’s fiduciary." As an adjective, the term means anything of or relating to holding something in trust for another. For example, you might say "The estate’s fiduciary heir is still a minor."