What is "melengestrol"

n. A steroidal progestin and antineoplastic.

Melengestrol ( INN, BAN) is a steroidal progestin and antineoplastic agent which was never marketed. An acylated derivative, melengestrol acetate, is used as a growth promoter in animals.

While melengestrol is sometimes used as a synonym for melengestrol acetate, what is usually being referred to is actually melengestrol acetate and not melengestrol.