Who Is the Spy? Rules and How to Play It Free

Updated 14 October 2026

"Who is the Spy" is a word party game where most players share a secret word, one or two players get a slightly different word, and nobody is told which group they are in. Everyone describes their word, everyone listens hard, and then the table votes out whoever sounds a little off. If you have been looking for a way to play the Who is the Spy game without cards or a host writing words on scraps of paper, Imposter Game's Undercover mode plays exactly this format, free, on one phone.

Where "Who is the Spy" comes from

In Chinese the game is called 谁是卧底 (shuí shì wòdǐ), which translates roughly as "who is the undercover agent". It became widely known in China after it was played regularly on Hunan TV's long-running variety show Happy Camp (快乐大本营), where celebrity guests described their words and tried to catch the spy. From there it spread to classrooms, dinners and phone apps, and English speakers now know it as "Who is the Spy", "Undercover" or simply the word imposter game.

We have not found a reliable source for who first invented it, so we will not guess. What matters is that the rules are simple, need no equipment, and work for almost any group.

Who is the Spy rules

Different groups and apps use slightly different versions, but the classic rules look like this.

1. Deal the words. Civilians all receive the same word. The spy (卧底, wòdǐ) receives a similar but different word. Some versions also include a "blank" player who gets no word at all.
2. Nobody knows their role. The spy is not told they are the spy. They only see their own word, so at first everyone assumes they are a civilian.
3. Describe in turn. Each player says one short description of their word without saying the word itself.
4. Vote. After a round of descriptions, everyone votes for the player they think has the different word. The player with the most votes is out.
5. Repeat or finish. In the traditional format, play continues round by round until the spies are all eliminated (civilians win) or only a small number of players remain with a spy among them (the spy wins). Many groups handle ties with a re-vote.

A quick example with a real pair from our Animals pack: civilians get "Crocodile" and the spy gets "Alligator". Civilians might say "Nile", "tears" and "Australia". The spy, thinking about alligators, says "Florida". That one clue is not wrong for a crocodile, but it sticks out, and the table starts to wonder.

How to play Who is the Spy free with Imposter Game

Imposter Game's default mode is called Undercover, and it is the same idea: the imposter secretly gets a similar but different word and does not know they are the imposter. Here is how a round works.

1. Open the game and pick a pack, several packs, or "Random mix". There are 25 packs with 40 pairs each.
2. Choose your players, or tap Quick Play to pick a number and start straight away. The game suggests 1 imposter for 3 to 7 players, 2 for 8 to 12, and 3 for 13 or more.
3. Pass the phone. Each player taps "I'm <name>", holds the card to see their word, releases to hide it, and passes it on. Turn on Strict mode if you want everyone to set a PIN.
4. A random first speaker and speaking order appear. Each player gives one clue without saying the word. Add a timer (1, 2, 3 or 5 minutes) if your group likes to debate.
5. Vote using a quick group vote or a secret vote on the passed phone. If the group votes out an innocent player or ties, the host can start another clue round with the imposter still hidden, just like the elimination rounds of the original party game.
6. Reveal. If the imposter is caught and Last chance is on, they can guess the civilians' word to steal the win.

One difference from the traditional version: Imposter Game plays one vote per round and then deals a new pair, rather than eliminating players over several rounds. Scores carry across rounds (civilians +1 each for a catch, imposter +2 for surviving, +1 for a correct last-chance guess), so the game still has a long-term winner. Groups who prefer the elimination style can keep playing the same pair verbally after a wrong vote as a house rule.

Start a Who is the Spy round

Tips for a better game

• Pick the right pack. For family groups, Kids (Easy) or Family Night keep things friendly. For film fans, try Movies or Bollywood. Browse all of them on the word list page.
• Do not be too specific. If you have "Coffee" and say "espresso machine", you have just handed the spy a big clue about your word. If they have "Tea", they may realise they are the odd one out.
• Do not be too vague either. "It's a drink" makes you look like the spy.
• Want a blank player? Switch to Classic mode. The imposter is told they are the imposter and gets no word, optionally with a hint. It is close to the "blank" role in some versions.

For full rules and settings, read how to play, or see our Undercover word game guide for strategy.

Playing Who is the Spy online

If your friends are on a video call or each want their own screen, the host can create an online room and share a 6-character code, an invite link or a QR code. Up to 15 players can join, everyone sees their own word, and everyone votes on their own phone. If someone refreshes, they rejoin the same seat. See imposter game online for the details.

FAQ

Is "Who is the Spy" the same as "Undercover"?

They are the same basic format: a majority word, a similar minority word, descriptions and a vote. Names and small rules vary between apps and groups.

Does the spy know they are the spy?

Not in the classic version, and not in Imposter Game's Undercover mode. The spy only sees their word and has to work it out from the other clues.

How many players do I need?

You can play with 3, but it is more fun with 5 or more. Imposter Game supports up to 20 players on one phone and up to 15 in an online room.

Is it free?

Yes. Imposter Game is free, with no login, no ads and no download.