Fiduciary
A person or firm legally required to act in your best interest, ahead of their own — a specific standard, not a compliment.
A fiduciary is a person or firm bound by law to put your interests ahead of their own when giving advice or handling your assets. It is a specific legal standard, not a marketing adjective. The duty includes acting with care, avoiding or disclosing conflicts of interest, and recommending what is best for you rather than what pays them best.
Registered investment advisers owe a fiduciary duty to their clients under the Investment Advisers Act. Not everyone who gives financial guidance is a fiduciary. Broker-dealers historically operated under a "suitability" standard, and now under the SEC's Regulation Best Interest — related but narrower than a full fiduciary duty. Insurance agents, bank employees, and many "financial advisors" operate under other rules again.
The question worth asking any adviser: "Are you a fiduciary in this engagement, in writing, at all times?" The answer, and its qualifiers, tells you the standard you are being held under — and the one they are.
Plumb is financial education, not financial, investment, tax, or legal advice.