I refer to those genera which have sometimes been called "protean" or "polymorphic," in which the species present an inordinate amount of variation; and hardly two naturalists can agree which forms to rank as species and which as varieties.
1897, Grant Allen, An African Millionaire
Dr. Beddersley came -- a dapper little man, with pent-house eyebrows, and keen, small eyes, whom I suspected at sight of being Colonel Clay himself in another of his clever polymorphic embodiments.
1996, Rod Ellis, Data abstraction and program design
Polymorphic redefinition in C++ is achieved by the use of virtual functions.