If you want to block someone on Skype without removing them from your contacts, then you should know that this is a very simple procedure. Alternatively, you can unblock this user at any time. If you block someone, that person will think that you are just offline.
Steps

Step 1. Launch Skype and sign in to your account

Step 2. Right click on the name of the contact you want to block and select "Block this user"

Step 3. Press the "Block" button to confirm this action
You can remove a contact from your notebook or report an abuse.

Step 4. Now you will see how the red circle crossed the cloud logo of this contact

Step 5. To unblock a contact, simply select this user, right-click and select “Unblock User”
It is so simple!!
Advice
- If you no longer want this person to be in your contact list, then in the drop-down menu, select the option "Remove from contact list".
- The blocked person will not know that you have blocked them. In his contact list you will always be "Offline" and he will not be able to send you chat messages or files.