What is Unlike?
1.
Taking back your approval of something that's been said or done, or something posted online.
This term originates from Facebook, where you can publicly say you "like" something, and then have the option to take the "like" back. "Unlike" does not mean you dislike something.
"I really like the shading and texture on this picture you drew of a man in a prison cell. Oh wait; the man is supposed to be me. Unlike."
See
2.
an expression used to indicate that you do not approve of whatever has just been said, or dislike it.
Originates from the ability to 'like' things on facebook and then 'unlike' them.
Guy 1: "Dude I just got the new Jonas Brothers album!"
Guy 2: "unlike..."
See