emerita/emeritae/emeritus/emeriti
correct Latin forms for f. sing. & pl., m. sing. & pl. As fewer people appreciate Latin distinctions, the pseudogeneric "emeritus" too often becomes the default. However, as these terms are rarely used without context, match the term to the individual(s). Better yet, be sure you need the word (as in a title). You might be talking simply about someone who has retired.
