What does ANNUS LUCTUS mean? May 25, 2017 All Dictionary ANNUS LUCTUS meaning in Law Dictionary the entire year of mourning. It was a rule one of the Romans, plus the Danes and Saxons, that widows must not get married infra annum luctus, (within the year of mourning.) Code 5, 9, 2; 1 Bl. Comm. 457.