What is a Wrongful Termination? Well, basically, wrongful terminations are instances in which an employee is fired for a discriminatory reason, which legally only include one’s race, religion, sex, or national origin, and sexual orientation is some states. Neither can you be fired for whistleblowing (see whistleblower laws) or retaliation (see employer retaliation). See also Constructive Discharge.
Nevertheless, it is not a wrongful termination to fire an at will employee for any reason that is not illegal, which currently includes anything from smelling badly to doing poor work to simply looking at your employer funny. So long as it is not based on a discriminatory factor, it is not deemed wrongful termination, even if it is patently unfair.