FIDUCIARY fi•du•ci•ar•y n. According to Merriam-Webster's Dictionary of Law, a fiduciary is “one often in a position of authority who obligates himself or herself to act on behalf of another (as in managing money or property) and assumes a duty to act in good faith and with care, candor, and loyalty in fulfilling the obligation”. n. According to the Certified Financial Planner Board of Standards, a fiduciary is “one who acts in utmost good faith, in a manner he or she reasonably believes to be in the best interest of the client”. n. According to NAPFA, “A financial advisor held to a Fiduciary Standard occupies a position of special trust and confidence when working with a client. As a Fiduciary, the financial advisor is required to act with undivided loyalty to the client. This includes disclosure of how the financial advisor is to be compensated and any corresponding conflicts of interest”.