To dishonour a person or a company is one of the unethical practices in a highly competitive market that consists in releasing generally false or partially true information in order to harm a particular person or company. Such defamation can cause considerable damage to the reputation.
Dishonour can be based on total lies or some sensitive or confidential information (typically health information or information about the number of complaints about a product or company and other shortcomings) that has leaked or has been stolen from a company or person (see Information Security attacks) or, for example, has been disclosed by a (whistleblower).
The first situation can hardly be avoided. However, it is possible to prevent leakage of sensitive information to unauthorized persons or, at least, to reduce the likelihood of such a situation by better protecting the confidential information.