I'm going to ghost my friend of 5 years
How are you planning to ghost your friend?
By never speaking to him again.
If your friendship is no longer working for you, then it's OK to choose to end it. However, you should explain to your friend why you're ending the relationship. Ending a friendship without any explanation is rude, and will lead to confusion and hurt feelings.
I want to end it, but I don't want to tell why.
Imagine if you were dumped by a significant other for no reason. You would feel upset by it. That feeling is the same you are doing to your friend.