Meaning of "tart" in slang.

Recently I heard a friend describing someone as a "tart" and when I asked what she meant by that she said "perra"(bitch). But on-line, and in several dictionaries, I've seen it is a very insulting word. Especially in Canadian (Ontario) slang, is it very offensive? Or can it mean something different from a prostitute but also a very flirtatious woman? Also, just for curiosity, were does this meaning come from?
Thanks for the answers.

<<she said "perra"(bitch). But on-line, and in several dictionaries, I've seen it is a very insulting word.<<

Like, perra is not a very insulting word?

Generally perra only means a woman who is flirts way too much woth too many people but it's never as insulting as Puta which implies it's for money and much more often.

<<perra only means a woman who is flirts way too much woth too many people<<

Cambridge dictionary definition of tart is allmost identical to your definition of perra:
http://dictionary.cambridge.org/define.asp?key=81418&dict=CALD

It's a nasty little insult that women use when talking about other women, or to men. I suppose men use it too, but I have not noticed it so much.
Rodrigo, honestly, your English is too good to be discussing that here. Just use a slang or an urban dictionary. When I get stuck on a questionable word in Spanish, I go to a Spanish Slang dicitionary before I approach other people.

I'm sure most of you recognize my posting style, but I'm not signing this one.

Thanks for the answers, I find a slang dictionary a VERY good idea. Does anybody know a good one? Or are there any on-line? I asked in the forum because slang words change throughout regions and I wanted to pinpoint the meaning my friend was trying to express.

http://www.urbandictionary.com/
Okay, Rodrigo, what else do you need?

Your Majesty is now satisfied Guest, you have have served your King.(?)

(?)?

I use (?) to show sarcasm, wikipedia has an article about the sarcasm mark and shows other ways to show it, of which (?) is the easiest to type.

<< I use (?) to show sarcasm >>

That's a bad idea, because it suggests something entirely different to me and probably everyone else. To me, it suggests something more like "I'm not sure about what I just said." Just because a symbol exists doesn't mean it's a good idea to use it.

- Kef

It doesn't make sense to me. Kef is right. If someone is helping you, I wouldn't respond with sarcasm.

I'm sorry, you are right. I really appreciate everybody's help but I misunderstood what Guest meant. We live in a global world and my friends understand what (?) means but I've just realised not everyone gets it. I also decided to use (?) because it's the symbol used in closed captioning but I think from now on I should probably write something easier to understand. Thanks for pointing out that that symbol is not universally understood, this being a forum about languages and communication, I think it is important to correct these ambiguities before we use them in situations where a misunderstanding could cause deeper trouble.
I really want to thank Guest, it was only that it sounded awkward to me and I assumed he was teasing but probably it was not the case.