Final answer:
Fiduciary duty is the duty to not obtain any advantage over a principal by misrepresentation, concealment, duress, or pressure. It is a legal and ethical obligation that requires fiduciaries to act in the best interest of the principal and avoid conflicts of interest.
Step-by-step explanation:
The duty to not obtain any advantage over a principal by the slightest misrepresentation, concealment, duress, or pressure is known as fiduciary duty. Fiduciary duty is a legal and ethical obligation, often associated with the relationship between a trustee and a beneficiary, or between a professional and their client. It requires the fiduciary to act in good faith, solely in the best interest of the principal, and to avoid any conflicts of interest.