fiduciary
This term carries a heavy legal and ethical weight, implying a relationship of absolute trust where one party is vulnerable to the actions of another. It is most frequently encountered in financial, legal, and corporate governance contexts, where the expectation is that the fiduciary will prioritize the client's needs above their own profit.
As a noun, the word refers to the entity holding the trust. As an adjective, it describes the nature of the obligation or the relationship itself. It is a formal term and is rarely used in casual conversation, appearing instead in contracts, statutes, and professional certifications.
Meanings
Involving trust, especially with regard to the relationship between a trustee and a beneficiary.
The board members have a fiduciary duty to act in the best interests of the shareholders.