So, in my humble opinion, based on my own experience, here is what I think:
1. A ghost is a human who has passed away but has not yet crossed over for various and assorted reasons. These can be harmless to fairly menacing depending on how they were in life and how they died.
2. A spirit is a human who has passed away, has crossed over and has chosen to come back to visit, usually to deliver a message to a loved one. They have a specific purpose for their visit and they don't stay very long. They also visit us in dreams. These are beneficial beings.
3. Entities are non-human, they can be 'alien' or from the 'demonic' planes, the 'alien' entities can be harmless to mildly frightening just out of the strangeness, whereas the 'demonic' entities are entirely malevolent and intend to do harm.
I believe it takes professional help to deal with these types of beings.
4. Angelic - Yes, there are angels and yes they do visit us. They are always benevolent and here to help us. They are always available and will always help if they are asked.
I hope that makes sense, I hope it helps. Feel free to disagree or add to the list.
