Noun | 1. | polymastigote - flagellates with several flagella flagellate, flagellate protozoan, flagellated protozoan, mastigophoran, mastigophore - a usually nonphotosynthetic free-living protozoan with whiplike appendages; some are pathogens of humans and other animals order Polymastigina, Polymastigina - small usually parasitic flagellates |