Synonyms for Alum (same or very similar meaning)
WordNet sense 1 (a white crystalline double sulfate of aluminum: the ammonium double sulfate of aluminum):
ammonia alum, ammonium alumWordNet sense 2 (a white crystalline double sulfate of aluminum: the potassium double sulfate of aluminum):
potash alum, potassium alumWordNet sense 3 (a person who has received a degree from a school (high school or college or university)):
alumna, alumnus, grad, graduate, graduateFrom the ODE community, based on WordNetadd/edit