ENGLISH
REFERENCE

ninja

n. · v. · adj.
US //ˈnɪndʒə// UK //nˈɪndʒɐ// nin·ja
  1. 1 historical warrior (n.)
    B1 Intermediate

    a person from Japanese history trained in secret fighting, hiding, and moving silently.

    a member of a class of 14th-century Japanese mercenaries trained in ninjutsu for espionage and assassination.

    Example

    The movie features a ninja who sneaks into the castle at night.

    Example

    Historical accounts of the ninja often blend folklore with reality, emphasizing their supposed ability to vanish using smoke and mirrors.
    • shinobi
  2. 2 expert or skilled person (n.)
    B2 Upper Intermediate Informal

    someone who is very good at a difficult job, especially in tech or business.

    a person who displays exceptional skill or agility in a specific professional field, often used in job titles or informal praise.

    Example

    Our office manager is a spreadsheet ninja who can fix any error.

    Example

    The company is looking to hire a coding ninja who can refactor their legacy codebase without disrupting the user experience.
  3. 3 to move or act stealthily (v.)
    B2 Upper Intermediate Informal

    to move very quietly and quickly so that nobody sees you.

    to move or perform an action with extreme stealth, speed, or agility.

    Example

    I managed to ninja my way out of the meeting before they gave me more work.

    Example

    He managed to ninja into the kitchen and grab a snack without waking the sleeping dogs.
  4. 4 internet posting (v.)
    C1 Advanced Slang Computing

    to post a reply on a forum just seconds before someone else does.

    to preempt another user's response in an online forum or chat by posting a similar comment moments earlier.

    Example

    I was going to give the answer, but you ninja'd me.

    Example

    It is common in fast-moving threads for several users to be ninja'd while attempting to provide the same technical solution.
    • preempt
  5. 5 stealthy or hidden (adj.)
    B2 Upper Intermediate Informal

    done in a very quiet or secret way.

    characterised by stealth or an inconspicuous nature.

    Example

    She made a ninja exit from the party because she was too tired to say goodbye.

    Example

    The software update included several ninja features that weren't mentioned in the official release notes.
Origin

A romanized borrowing of Japanese 忍者 (ninja), popularized within Japanese by manga after World War II and in English by Eric Van Lustbader's 1980 novel The Ninja and the 1981 movie Enter the Ninja, of uncertain derivation but with an underlying sense of secret or hidden person. The “Mongolian miner” sense arose from the supposed resemblance of the bowls used to wash ore with mercury to the shells of the Teenage Mutant Ninja Turtles. The Juggalo slang sense arose via influence from AAVE nigga.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Related words

Last updated June 20, 2026