A chimera is something you’ve imagined that’s bits and pieces of other things mashed together into a new horrible fantasy, something impossible in real life that only exists in your mind.
In Greek mythology, a chimera is a monster that has a lion’s head, a goat’s body, and a serpent’s tail. And it breathes fire. No creature like that has ever existed, but the idea seemed real and terrifying to Greeks, and that’s another meaning: an idea that feels real but is impossible, like the idea of a world without evil. Pronouncing the word is very possible though; just try it one of two ways: either kye-MEER-uh or kih-MEER-uh. Both work.