ninja

ninja — noun

1. A warrior in old Japan who was trained to move quietly and stay out of sight, sk

1.nounB1
Definition

A warrior in old Japan who was trained to move quietly and stay out of sight, skilled at using a short sword and sometimes hired to spy on or attack enemies secretly.

Example

In 15th-century Japan, Hiro spent years training to become a ninja in his village.

collocation: train to become a ninja

The old scroll described how ninjas could climb castle walls without making any sound.

described how + ability clause

Common collocations
  • ninja training
  • ninja weapons
  • ninja skills
  • ninja clan
  • ninja warrior
  • ninja costume
  • become a ninja
  • train as a ninja
Synonyms
  • shinobi

    The original Japanese term for ninja; less common in English but used by enthusiasts and in historical texts.

  • spy

    Focuses on the information-gathering role but does not imply combat skill or the Japanese cultural origin.

  • assassin

    Highlights the killing-for-hire aspect but carries a modern, criminal connotation that historical ninja did not always have.

  • stealth operative

    A modern military term that captures the secretive movement aspect but lacks the historical and cultural specificity.

Antonyms
  • samurai

    A samurai fought openly, followed a strict honour code (bushidō), and belonged to the noble warrior class — the direct social and tactical opposite of a ninja.

Grammar Patterns

ninja + noun (as modifier)

the + ninja / ninjas

Usage Note

The plural form 'ninja' (without -s) is often used when referring to the historical group as a collective, while 'ninjas' is common in modern contexts such as films, games, and everyday conversation. As a modifier, the singular form is always used: 'ninja training', 'ninja weapons'.

Common Mistakes

Samurai and ninja were the same kind of Japanese warrior.
Samurai were noble warriors who followed a strict code of honour, while ninja were covert fighters who used stealth and espionage.
The two groups belonged to very different social classes and fighting traditions in Japanese history.
The ninja was a kind of soldier who fought in open battles.
Ninja rarely fought in open battles
they were trained to work secretly, gathering information and carrying out surprise attacks.' — Ninja were special forces for spying and covert operations, not frontline soldiers.

Word family

  • ninjutsu
    nounC1
  • shinobi
    nounC2

Synonym discussion

Sense: noun/1

These four words overlap with ninja but each has a distinct meaning. A samurai was a noble Japanese warrior who followed a strict code of honour (bushidō) and fought openly in battle — the social opposite of a ninja. A spy gathers secret information but may have no combat training, whereas ninja were always fighters. An assassin kills people for payment, which is a narrower, darker role than the ninja's broader duties of espionage, sabotage, and scouting. A warrior is the most general term — any person skilled in fighting — so it lacks the specific Japanese stealth tradition. For example, a history book might say 'the samurai despised the ninja as dishonourable fighters,' showing the contrast, while a film review might call a character a 'ninja-like spy' to emphasise the covert aspect over the fighting skill.

samurai ↗spy ↗assassinwarrior ↗

Etymology

JapaneseEnglish

The word 'ninja' comes directly from Japanese 忍者, made up of the characters 忍 (nin, meaning 'to endure' or 'to hide') and 者 (ja, meaning 'person'). So a ninja is literally an 'enduring person' or 'hidden person'. The term entered English in the mid-20th century through books about martial arts and Japanese history, and became widely known through films, comics, and video games from the 1980s onwards.