Nemo debet bis vexari (pro una et eadem causa)

Roughly translates as “No one should be tried twice in respect to the same matter.”

This is a Latin saying that expresses what in criminal law is known as the rule against double jeopardy, ie the notion that a person should not be “vexed” or have to answer for themselves by being tried or punished more than once for any particular accusation brought against them. In civil law it means a person should not be sued more than once over the same dispute.

See also: Autrefois acquit, Double jeopardy, Estoppel, Res judicata