I suppose you are asking for this because you'd like to sync your Windows Phone contacts only with Outlook.com.
In Outlook.com choose contacts from the pop-up list (the arrow next to outlook logo on the left) and there choose import from .CSV file (you must have exported first your contacts in contacts.google.com to a .csv file).
After the import is completed you should check all your info is now on outlook.com, in case you have linked it with Google you can now revoke access to Google and just keep using Outlook.com