snitch

To inform on someone, especially in betrayal of others.

To contact or cooperate with the police for any reason.

To steal, quickly and quietly.

Besides, I shall require your help in snitching the pig. But I was forgetting. You are not abreast of that side of our activities, are you? Emsworth has a pig. The Duke wants it.

A thief.

An informer, one who betrays their group.

A nose.

'Yah, I wouldn't git a second-'and dress at a pawnbroker's!' 'Garn!' said Liza indignantly. 'I'll swipe yer over the snitch if yer talk ter me. [...] "

He added in conclusion that he strongly disliked the police coming and sticking its nose into his affairs and, since the horror which such actions inspired in him was not far from making him wish to vomit, he extracted from his pocket a silken square of the colour of the lilac flower (the one that isn’t white) but impregnated with Barbouze, the Fior perfume, and with it dabbed his snitch.

A tiny morsel.

"He pays for the food you eat," said the woman. "Yeah," said the boy. "And I earn every snitch doing everything ever gets done around here."

A ball used in the sport of Quidditch: the Golden Snitch.