Fabian bet
An agreed proposition in which one of the people taking part cannot lose money or items but can gain them
john betted sophie 5 english pounds that he could jump the wall. However he did not jump it but he did not have to pay because it was a "Fabian bet".
the next day John jumped the wall which subsequently meant that sophie lost 5 pounds whilst john gained
the next day John jumped the wall which subsequently meant that sophie lost 5 pounds whilst john gained