unfriend

One who is not a friend; an enemy.

It is even as I suspected, my lord, […] Ye have back-friends, my lord, that is, unfriends—or, to be plain, enemies—about the person of the Prince.

I wonder often it has not drawn her out of the grave to come and stand before me, and hear me tell her how I loved her. For, sir, we parted unfriends.

To sever as friends.

"I hope, sir, that we are not mutually Unfriended by this Difference which hath happened betwixt us."

To defriend; to remove from one's friends list (e.g. on a social networking website).

"I asked her why, she said it was because I didn't comment, and I shrugged and said whatever. I didn't unfriend her."

Without unfriending someone, you can now choose to limit or block (unsubscribe) someone from your newsfeed or choose to see only what Facebook deems as very important.