I don't see what's so hard to understand; they're made-up names of made-up concepts that derive from real life words and concepts.
A "mutt" generally refers to a dog with the DNA of two different breeds, i.e. a mixed-breed dog. A mutation is a permanent change in DNA sequence. By calling the lab-bred creatures in her series 'muttations', she is referring to how they are all those creatures have DNA of two different species, mutated to form a whole new kind of creature, or a 'mutt'.
I don't understand why you have a problem with childish-sounding names. Just because something sounds 'stupid' to you doesn't make her illiterate, since the reasoning behind the name 'tracker jacker' is solid (i.e. they 'track' their victims to attack them, and in Mockingjay, it's explained that their venom can be used to 'hijack' an individual. I'll bet you would have something to say about her use of the term 'hijack' as well.).
Point is, the series is hers. It doesn't make her illiterate if she wants to call morphine morphling, not to mention, aside from the ability to make the user not feel pain, morphling is actually not the same as morphine. Illiteracy refers to the inability to read or write, and I believe she wrote at least this one trilogy here. Whether or not you think it is well-written (and might I add, your opinion seems to be strictly based on her use of certain words to name and create her own concepts, you mentioned nothing about her actual writing abilities) is subjective, but she can definitely write.
- As I mentioned and explained, "muttations" =/= mutations, they are mutations of sorts, but the use of DNA of two different species is what makes them 'muttations', therefore they are not simply 'mutations', therefore she would not use the word 'mutations'. She can, but it's not wrong of her to coin a new, more specific term that more accurately describes these mutations.
As I also mentioned and explained, "morphling", aside from its ability to make its user not feel pain, is not the same as morphine, therefore she would not use the word 'morphine'. It's a drug that's LIKE morphine. I'll put a link in the sources that further discusses the differences between morphling and morphine, if you are actually interested, and not just trying to knock the series.
- Combining DNA. I'm sorry, I didn't know I had to spell out everything for you, I assumed you were capable of putting two and two together, and understand the simple concept of how she used the definition of 'mutt' to refer to the DNA of two different creatures being put together. At least you got the 'mixed-breed' part, good for you. She is simply using the term to indicate that they are using DNA of two different species being put together, LIKE a mutt. If she were actually referring to dogs, she would have just said mutts (which, yes, they are sometimes shortened to, but obviously in their time it has a newer meaning), but she combined the words 'mutt' and 'mutation' to reflect on the nature of these creatures more accurately.
- But she doesn't use it to match the current definition of the word 'hijack', which refers to the taking over of something mechanical, or an aircraft or bus or something, not a person. I assumed you would have an issue with that since you seem very obsessed with keeping words 'true' to their definitions, but I guess you just have a problem with neologisms.
- By "she can definitely write", I meant it in the very literal sense. She has written a book, like how I am writing a comment, like how you wrote that question/rant disguised as a question (or type, if you prefer), therefore she is not illiterate, and I am not illiterate, and you are not illiterate. You know, since we can all read. And write. Literally. Good or bad is subjective. And "subjective" means you are entitled to your own opinion. Which was what I meant when I said whether or not her series is well written is subjective. I was merely pointing out we are all literate by showing that we can read and write. Even with your lack of comprehension skills, I would consider you literate.
" Right you are, so perhaps you're illiterate since I mentioned that it wasn't these idiotic words that made her illiterate."
I'm aware you mentioned in your initial comment that "Also, I didn't say it was those words that made her illiterate. It's her writing skills that prove she's illiterate", but you see, in saying this, you are not providing any comments of any real substance with anything to back up your statement, and that was what I meant by you not saying anything negative about her writing other than her use of modified English words.
I can re-explain everything more thoroughly if you still have difficulty understanding basic English and Suzanne Collins' neologisms, but I'm afraid I'm running out of space.