Final answer:
Insider trading is the term used to describe the act of using confidential information to trade in violation of the duty of confidentiality.
Step-by-step explanation:
The term used to describe the act of using confidential information to trade in violation of the duty of confidentiality is insider trading. Insider trading occurs when individuals buy or sell stocks or securities based on non-public information that they have access to due to their position within a company. This practice is illegal because it gives those individuals an unfair advantage and undermines the integrity and fairness of financial markets.