Retaliation is essentially taking action against an employee because the employee engaged in some type of activity that is protected by law. The law breaks it down into three parts, each of which the employee has to prove:
1-The employee engages in some type of legally protected activity(more on this below).
2-"Adverse employment action" is taken by the company.
3-There is a "causal nexus" (that's "connection" to you and me) between the protected activity and the adverse action. In other words, there has to be some reason to believe that the adverse action was taken because of the protected activity.
Almost all federal and state employment laws have anti-retaliation provisions. In the labor relations arena, the "non-discrimination" provisions in the National Labor Relations Act are essentially anti-retaliation provisions. A wrongful discharge lawsuit where an employee claims he was terminated for refusing to break the law or for complying with the law is also essentially a retaliation claim.
"Protected activity" can include such things as filing a charge or lawsuit, providing truthful testimony or other help to someone else in connection with a charge or lawsuit, or making an internal complaint about unlawful practices. These activities may be protected even if the employee is wrong -- as long as the employee had a good-faith belief that the employer's conduct was illegal. (Sometimes the employee's belief must also be objectively reasonable to be protected -- check the relevant law and the interpretations from courts in your jurisdiction.)
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