Quite simple. Players think of something and give FOUR Clues to guess it. Pretty easy, right?
Wrong. ONE of the Clues is an IMPOSTOR. It misguides you into thinking something else.
So, let's play!

I'll start.
1. She is clever.
2. She is a pure-blood.
3. She got ten OWLs.
4. She hates Quidditch.

Please mention the player who guessed correctly and tell him to give clues.

Hermione?

Do we think of the character, or do we say which one is the imposter?

If version two then
2. She is a pure-blood

You're right @Amelia Lerelle and @ Edith Walkers

Btw you have to say both, which clue is the impasta and which one's the answer. Amelia, you said it first, so you give four clues next… with one impostor

@Julia Evans You have to say both

@Amelia Lerelle your turn to give clues

I’m out and quite busy at the moment, so @Edith Walker, you may go

If you mention me, my surname has an 's' at the end of it Amelia. George Calder you can't dp

1.) They were loyal to Dumbledore
2.) They were a Metamorphmagus
3.) They were male
4.) They were half-blood

Nymphadora 'dont call me that' Tonks
The third clue was fake
@Edith Walkers

Your turn @Natasha Jones