fiduciary

noun | \ fə-ˈdü-shə-rē, -ˈdyü-, -shē-ˌer-ē \ | fi·du·cia·ry

1. : 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 : one (as an agent) having a fiduciary duty to another — see also fiduciary duty at duty, fiduciary relationship — compare principal

adjective

1. : of, relating to, or involving a confidence or trust a guardian acting in his fiduciary capacity

2. : of or relating to a fiduciary or the position of a fiduciary a fiduciary bond