The word "emeritus" is used to describe someone who used to hold an important position or title but is now retired. It is an honorary title given to recognize their previous achievements and contributions. Full definition
2001): A member of the Sculptors Guild, Nickford held the title of Professor Emeritus of Art at City College of New York. (cintasfoundation.org)
Robert Linn, distinguished professor emeritus of education at the University of Colorado at Boulder, says that the work of PARCC and Smarter Balanced represents the «closest in my professional career that we've had this sort of challenging test.» (ascd.org)
Distinguished professor emeritus at University of California, Davis, School of Veterinary Medicine and member of National Academy of Medicine (veterinarypracticenews.com)