nin·​ja | \ ˈnin-jə How to pronounce ninja (audio) , -(ˌ)jä \
plural ninja also ninjas

Definition of ninja

: a person trained in ancient Japanese martial arts and employed especially for espionage and assassinations

Keep scrolling for more

Did You Know?

Ninjas may seem mysterious, but the origin of their name is not. The word ninja derives from the Japanese characters "nin" and "ja." "Nin" initially meant "persevere," but over time it developed the extended meanings "conceal" and "move stealthily." In Japanese, "ja" is the combining form of sha, meaning "person." Ninjas originated in the mountains of Japan over 800 years ago as practitioners of ninjutsu, a martial art sometimes called "the art of stealth" or "the art of invisibility." They often served as military spies and were trained in disguise, concealment, geography, meteorology, medicine, and also other martial arts. Popular legends still associate them with espionage and assassinations, but modern ninjas are most likely to study ninjutsu to improve their physical fitness and self-defense skills.

Examples of ninja in a Sentence

Recent Examples on the Web However, Mass Effect 3 introduced the cyber-ninja villain Kai Leng. George Yang, Wired, "Orientalism, Cyberpunk 2077, and Yellow Peril in Science Fiction," 8 Dec. 2020 The story takes place 20 years beyond where the ninja turtles are in their main series, Eastman says. David Betancourt, Washington Post, "A Teenage Mutant Ninja Turtles co-creator has a long-lost story to tell. And it gets pretty dark.," 28 Oct. 2020 Her sweetly silly ninja moves in preparation for the pettiest of postal thefts. Joe Morgenstern, WSJ, "‘Kajillionaire’ Review: Lowbrow Larceny," 24 Sep. 2020 The ninja were seen as covert agents of feudal Japan, who relied on espionage and strategy. David Aaro, Fox News, "Thieves sneak in, carry out heist at Japanese ninja museum," 21 Aug. 2020 Deep down, beneath the bluster and the burn, Hamler is a details ninja. Sean Keeler, The Denver Post, "Why Broncos fans are going to fall in love with KJ Hamler — instantly," 7 June 2020 For Sombra to come out of the woodwork, Decay may need to take the reins on Overwatch’s cyborg ninja. Sean Collins, Dallas News, "Era of the Genji: Why the current Overwatch League meta could be a boon for the Dallas Fuel," 2 July 2020 The master's degree course started in 2018, a year after Mie University established the International Ninja Research Center in Iga -- the first in the world dedicated to the ninja studies. Yoko Wakatsuki And Nectar Gan, CNN, "Meet the Japanese man who holds the world's only master's degree in ninja studies," 30 June 2020 At its peak, there are 150 ninjas and 30 mentors in the program. Vincent T. Davis,, "CoderDojo Collaborative teaches San Antonio kids coding classes for free," 25 May 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'ninja.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of ninja

1964, in the meaning defined above

History and Etymology for ninja

Japanese, from nin- persevere, conceal, move stealthily + -ja person

Keep scrolling for more

Learn More about ninja

Time Traveler for ninja

Time Traveler

The first known use of ninja was in 1964

See more words from the same year

Listen to Our Podcast about ninja

Statistics for ninja

Last Updated

17 Dec 2020

Cite this Entry

“Ninja.” Dictionary, Merriam-Webster, Accessed 18 Jan. 2021.

Keep scrolling for more

More Definitions for ninja


How to pronounce ninja (audio)

English Language Learners Definition of ninja

: a fighter who is trained in the Japanese martial arts


nin·​ja | \ ˈnin-jə How to pronounce ninja (audio) \
plural ninja also ninjas

Kids Definition of ninja

: a person trained in ancient Japanese martial arts who works as a spy and assassin especially in the past

Comments on ninja

What made you want to look up ninja? Please tell us where you read or heard it (including the quote, if possible).


Test Your Vocabulary

Words of Snow and Ice Quiz

  • image1037863653
  • Which of the following refers to thin, bending ice, or to the act of running over such ice?
True or False

Test your knowledge - and maybe learn something along the way.


Anagram puzzles meet word search.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!