https://en.wikipedia.org/wiki/Unclean_spirit
The term spiritually unclean (disease of the soul) is not often heard these days, and is sometimes associated with religious zealots. However it is in fact a reality of our third dimensional world whether you are religious, spiritual or what ever. This is a low dark vibrational density or world (duality) that we live in.
Examples of an unclean soul or spirit are constantly around us every day, we cannot avoid this. But we can choose not to follow these spiritually unclean people, some of which are famous people or just individuals that we know in our every day life. It is their actions and mindset that make them "unclean" spiritually, through immoral behaviour , violent behaviour etc.
I, myself do not have a religion, but I have very strong spiritual beliefs and values. You do not have to be like me. I am not telling anyone what they should or should not do, other than be the best person that you can be, lets you fall in to the trap of negative behaviour and live that way. Yes entity attachments can also affect our behaviour and are also in the classification of being unclean spiritually, but this can be fixed by an energy clearance being done on the individual, not to be confused with mental health issues. That is a different matter entirely.
That is basically what an unclean soul is.They can change if they want to, but that is up to the individual, it is their choice. It is our individual choice not to associate with them lets we become like them.
https://alexfulfordclairvoyantmedium.blogspot.com/2019/01/disease-of-soul-we-all-have-it.html