Someone who tells another person information you don’t want them to find out. They tend to be a sibling of yours
McKayla, my little sister, snitched to my mom about how I broke my phone
Someone who tattles or informs another person's misdeed to authority figure. Usually about a minor offense.
Man: taking pictures in a store
Snitch: What are you doing?
Man: Taking some pictures of these items I was thinking about buying.
Snitch: runs to the store's management Some guy is taking pictures of items in your store.
Store Manager walks up to customer: Excuse me, sir, we don't allow pictures in our store. You'll need to leave.
Man sees the snitch as he exists the store. Looks at the snitch and says: Snitch!
A snitch is a pathetic piece of garbage that can't believe that life is going well for others and therefore must put others down in order to get off on it.
John: "I can't believe there's a snitch in our group! Why must they be so disgusting?"
Jane: "Yeah, that person's a motherfucking cunt."