This means your annual gross salary is higher than the minimum wage established by law for your specific level of experience. "Super minimum" (”superminimo” in Italian) is the part of your salary that exceeds the mandatory minimum wage. Based on this clause, if the mandatory minimum salary will increase, then your annual gross salary is going to remain the same. The part of your salary which exceeds the minimum wage will absorb that increase. While it would absorb any eventual increase of the mandatory minimum salary, this is not related to any salary increase that you might receive from the company based on your performance or any other internal policy. The company is allowed to increase your salary.