忍者龟 rěnzhěguī Teenage Mutant Ninja Turtles Origin Definitions Defs Strokes Stroke Words Sentences Sents 忍者 rěnzhě noun ninja a person trained in the ancient Japanese art of ninjutsu, specializing in gathering intelligence and espionage; equivalent to a modern spy龟 龜 guī noun tortoise tortoise; turtle; shell of a tortoise used for divination in ancient times