when someone does something illegal or wrong with money that they are trusted to take care of, or when someone fails to do something that they have been trusted to do as part of their job:
• The former Minister was found guilty of appropriation of public funds, forgery and breach of trust.
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breach of trust UK US noun [C or U] (plural breaches of trust)
► LAW a failure to act responsibly for someone who has given you something to keep safe, for example money or a company's secret information: »
The company initiated legal proceedings alleging industrial espionage and breach of trust.
»Investors are claiming losses as a result of a breach of trust by the bank.
Financial and business terms. 2012.