ninja
Americannoun
plural
ninja, ninjas-
(often initial capital letter) a member of a feudal Japanese society of mercenary agents highly trained in martial arts and stealth ninjutsu, who were hired for covert purposes ranging from espionage to sabotage and assassination.
-
a person who is expert or highly skilled in a specified field or activity (often used attributively).
marketing ninjas; ninja programmers.
verb (used with object)
noun
Etymology
Origin of ninja
First recorded in 1960–65; from Japanese, equivalent to nin- “endure” + -ja, combining form of -sha “person, agent” (from Middle Chinese, equivalent to Chinese rěn + zhě )
Explanation
A ninja was a skilled fighter in feudal Japan, starting in the fourteenth or fifteenth century. Today, people like to call themselves ninjas for doing anything well — from making a touchdown to surviving a treacherous obstacle course. The original ninjas were mercenary warriors and spies, and the methods they used were looked down on and considered dishonorable by the highest caste, the samurais. Ninjas were so fascinating and frequently discussed that they gained mythological status — in stories, people credited them with invisibility and the ability to walk on water, among other skills. In Japanese, the word ninja means "spy."
Vocabulary lists containing ninja
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Robinson also created other videos depicting Pitt battling a sword-wielding "zombie ninja," and another showing him teaming up with Cruise to fight a robot.
From Barron's • Apr. 24, 2026
"Background actors are like ninjas, and only ninjas can determine who else is a good ninja," Amaya told AFP.
From Barron's • Feb. 17, 2026
After the house fell silent, they rifled through pockets of clothes inside the closet, finding a manicure kit and a ninja star inside a box of childhood mementos.
From Los Angeles Times • Aug. 8, 2025
Mark Joseph Stern: This is a classic Kagan ninja move.
From Slate • May 16, 2025
Every now and then, though, Zion and I would have to do some serious ninja blocks when a pretzel or grape flew at our heads.
From "Insignificant Events in the Life of a Cactus" by Dusti Bowling
![]()
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.