Katniss is irritated when Gale suggested them leaving. She reacts harshly because she wants to stay and take care of her family.
Well, most slang words that have been used for a long period of time have been added to the dictionary, but then again, some other slang words have not. So, it really depends on the word.
But, for a straightforward answer i would say yes, just because some slang words are in the dictionary.
~Hope this helped