According to the novel, To Kill A Mockingbird, Scout is a young narrator. She starts off the book at the age of 6. A few characteristics stand out. First, she is intelligent. She knows how to read and she is more intelligent than her classmates. This is why she gets bored in school.
She is also a tomboy. In fact, the boys in her class are afraid of her, as she has a combative streak. She gets into a few fights and wins.
As for a physical description there is little, but we can fill in a few details.
I could not possibly hope to be a lady if I wore breeches; when I said I could do nothing in a dress, she said I wasn't supposed to be doing things that required pants. Aunt Alexandra's vision of my deportment involved playing with small stoves, tea sets, and wearing the Add-A-Pearl necklace she gave me when I was born...
It is probably best that there is no clear description of Scout. In this way, we can use our imaginations.