monomastigote

mon·o·mas·ti·gote

(mon'ō-mas'ti-gōt),
A mastigote having only one flagellum.
[mono- + Roman mastix, a whip]

monomastigote

(mŏn-ō-măs′tĭ-gōt) [″ + mastix, whip]
A protozoan possessing only one flagellum.