Criminal conversation: synonymous with adultery.
In old English law, this was a claim for damages the husband could institute against the adulterer. The action was abolished in England 1857 but lived on in Canada (for a while).
In Canada, Coles v Roach, a 1980 Newfoundland case (68 APR 172), Justice McQuaid wrote:
"The gist of the action of criminal conversation is not merely the loss of the society, comfort, and assistance of the wife, but it includes also the wrong done by the intolerable insult to which (the husband) has been subjected by the corruption of his wife.
"Its essence is the adultery between the wife and a third party. It is no defence that the wife was a willing participant in the adultery, or indeed, even the instigator of it, for the action is grounded , in common-law, on the principle that the wife was incapable of giving any consent to her own adultery, considered, as she was, something in the nature of a servant or chattel of her husband. Lord Tennyson put it this way: 'Something better than his dog, a little dearer than his horse.'"
This ancient and obviously outdated cause of action has been abolished in Alberta, British Columbia, Saskatchewan and Manitoba and is on probably on shaky legal grounds elsewhere in Canada given the Charter of Rights and Freedoms.
BC's legislation (Family Relations Act) reads, at s. 123:
"An action must not be maintained for restitution of conjugal rights, loss of consortium, criminal conversation or jactitation of marriage."