Namaste = Basically (I say basically because there is an in-depth meaning that requires more time and space than I have right now) means
"The White Light In Me Salutes The White Light In You"
It is a term honoring anothers spirit. I had a mentor who preferred to call it the Christ light; and yet others have called it something else. Whatever one calls it, it is still honoring the core of our being. That which does not die. No matter what we may do or say here on this earth plane, we are still part of the whole and that part of us is pure.
There is much more to study on this salutation if one is so inclined. These are just basic definitions.