The four letters in our particular alphabet, s, o, u and l, form what is called a 'word'. This word is used in language to talk about one aspect of our personality/character, call it whatever you like - the word spirit would do just as well, but it uses up a fraction more energy to say it. The word, soul, enables us to think more directly about the aesthetic side of humans. We know that all our ideas, thoughts, images, etc emanate from our brains, themselves made of physical matter. Without the physical brain, functioning because we are alive and it has oxygen etc to enable it to work, we do not have life, let alone an aspect labelled 'soul'.
What it is NOT is something separate from the integrated human body.
\it is a useful word, but, like God, is entirely an idea in the brain.
Will that do?!!