supererogatory /-ə-rogˈə-tər-i/, also (rare) supererogant /-erˈō-gənt/ or supererogative /-ə-rogˈə-tiv/ adjective

works of supererogation (RC)

Works which, not absolutely required of each individual for salvation, may be done for the sake of greater perfection, affording the church a store of surplus merit, to eke out the deficient merit of others