"why do atheists always avoid defining for me what they mean when they use the term 'God'"?
Because that is potentially an endless subject.
"Well, what if god had blue eyes?"
No, I don't believe such a god exists.
"Well ... what if God had red eyes and a blue tongue."
"What if god had no god or corporeal form?"
"What if god was EVERYTHING?"
Why use such a loaded term as god to describe a common concept?
"But what if god is just the good stuff?"
and so on...