in the classroom

[blouen]

In a classroom for example, than when somebody is cheating and a classmate told the teacher the misdeed.

* What do you call the thing that the classmate did?
* What do you call the classmate?

[Anglika]

In a classroom for example, when somebody is cheating and a classmate tells the teacher about the misdeed.

* What do you call the thing that the classmate did?
* What do you call the classmate?

He tells on the culprit and he is a tell-tale or snitch.

[blouen]

He tells on the culprit and he is a tell-tale or snitch.

Don't we have a one-word term form what he did instead of the phrasal "tells on"

[Anglika]

I suppose you can say he snitches on the culprit or he sneaks on the culprit.

[Naamplao]

Don't we have a one-word term form what he did instead of the phrasal "tells on"

In negative slang terms the informing classmate is "ratting" on his fellow classmate. The person is a "rat"

[blouen]

Jack called Ana a rat when he discovered that she has been snitching/sneaking on her classmates.

[riverkid]

In a classroom for example, [than] when somebody is cheating and a classmate told the teacher about the misdeed,

* What do you call the thing that the classmate did?
* What do you call the classmate?

I agree with most of the terms that have been given for this but isn't it rather ironic that we use pejorative names for those who do what's right?