Latin for Lawyers translates it as:
"That to which a man consents cannot be considered an injury."
Sometimes truncated to volenti.
Also, voluntary assumption of risk, or damage by consent, is not a cause of action.
Volenti non fit injuria is a defence in tort that means where a person engages in an event accepting and aware of the risks inherent in that event, then they cannot later complain of, or seek compensation for an injury suffered during the event. This is used often to defend against tort actions as a result of a sports injury.
The volenti maxim has had a colurful past.
In one olde case (Wilson v Glossop), a husband sued his wife for damages as a result of her alleged adultery. The claim was barred as the evidence revealed that he had connived in the adultery.
In another case, in an era when spring-guns were not illegal, a man was hurt by the gun after having been warned by the landowner of it. The maxim prevented his claim for damages (Ilott v Wilkes).
Similarly, a person who crosses a barrier into a leopard cage to retrieve a smouldering cigarette, and gets mauled by the leopard, was prevented from suing based on the volenti maxim (Sylvester v Chapman).
Judicially, the expression is still alive and kicking.
In a 1986 Supreme Court of Canada decision, Dunbar v Labar, Justice Estey wrote:
"(V)olenti will arise only where the circumstances are such that it is clear that the plaintiff, knowing of the virtually certain risk of harm, in essence bargained away his right to sue for injuries incurred as a result of any negligence on the defendant's part.
"The acceptance of risk may be express or may arise by necessary implication from the conduct of the parties, but it will arise, in cases such as the present, only where there can truly be said to be an understanding on the part of both parties that the defendant assumed no responsibility to take due care for the safety of the plaintiff, and that the plaintiff did not expect him to.
"Common sense dictates that only rarely will a plaintiff genuinely consent to accept the risk of the defendant's negligence.
"Glanville Williams wrote that 'the defence must be restrictively construed.... In almost every negligence action of modern times where the defence of volens has been raised it has failed. This is because the cases in which a person truly consents to run the risk of another's negligence are altogether exceptional.'"
Six years later, in Hall v Hebert, Mr. Justice Cory wrote:
"Another mechanism aimed at limiting the scope of tort actions is the defence known by the maxim volenti non fit injuria. The maxim stands for the proposition that no injury is done to one who consents. The defence applies both to intentional and accidental harms....
"No matter how the maxim or principle is characterized, volenti non fit injuria .... constituted an absolute bar to recovery.... Yet it has, in recent years, been severely restricted in its application.
"In order for the doctrine of volenti to apply, there must be either an express or implied assumption of the risk of the activity which caused the damage... (B)oth parties to the activity must have agreed that they would participate in it regardless of the risk of injury and give up their right to sue should injury occur as a result of the agreed upon activity."