It means that the marriage took place at a time in the year when weddings were normally not permitted (i.e. Advent or Lent). The priest obtained a dispensation to have the wedding on that date.
Prior to the 1917 Code of Canon Law the solemn celebration of marriage was not permitted from Advent to the Epiphany or from Ash Wednesday to Low Sunday. The 1917 Code of Canon Law permitted marriage any time but did not permit the solemn nuptial blessing during Advent or Lent. This, like the previous impediment, could be dispensed from by the local Bishop.
Today, the Rite of Marriage simply notes: “When a marriage is celebrated during Advent or Lent or other days of penance, the parish priest should advise the couple to take into consideration the special nature of these liturgical seasons.”
