Ex turpi causa non oritur actio (Latin for "from a dishonorable cause an action does not arise") is a legal doctrine which states that a claimant will be unable to pursue a cause of action if it arises in connection with his own illegal act. Particularly relevant in the law of contract, tort and trusts,Winfield & Jolowicz on Tort, 15th edition, 866, suggest that the doctrine should be purely confined to contract ex turpi causa is also known as the "illegality defence", since a defendant may plead that even though, for instance, he broke a contract, conducted himself negligently or broke an equitable duty, nevertheless a claimant by reason of her own illegality cannot sue.