A whisteblower is a person that tells something to the public which is related to private affairs of the business the person works in and which is considered confidential and protected information. In many cases, the whistleblower is breaking the law because they have signed a non-disclosure agreement with their employer to not tell anything public. In most cases, whistleblowing is done for the public good. In all cases, it is to highlight wrongdoing and law breaking of a particular company and usually particular employees within the company..
When a person comes forward in the capacity of a whistleblower the law allows a protected status in certain regards. The one legal right that is afforded to whistleblowers is that they will not be held liable to their company for breaking the terms of their NDA if the submissions they give are in the public interest.