Delictum

[Latin, A fault.] An injury, an offense, or a tort—a wrong done to the property or person of another that does not involve breach of contract. Culpability; blameworthiness of a criminal nature, as in the Latin phrase in pari delicto—in equal fault or equally criminal—used to describe accomplices to a crime.

An actio ex delicto is a lawsuit based upon the commission of a TORT, as opposed to an actio ex contractu, an action for breach of contract.