wrongful termination in violation of public policy

Definition from Nolo’s Plain-English Law Dictionary

A legal claim that an employee has been illegally fired for reasons that most people would find morally or ethically repugnant. In many states, for example, an employee can sue for wrongful termination in violation of public policy after being fired for (1) exercising a legal right, such as voting, (2) refusing to do something illegal, such as submitting false tax returns or lying on reports the employer is required to submit to the government, or (3) reporting illegal conduct.

Definition provided by Nolo’s Plain-English Law Dictionary.