a person who is fake and pretends everyone is there best friend. Usually they come off to nice and kind, and you never hear from them until they either need you or they feel lonely.
Ted : That person is such a flakered.
Chris : Yeah, yesterday she came to my house and I havent seen her in years.
A post put up onsocial media by a flake made to suggest that they aren't feeling well, made in advance of an event, so that they have a history of not feeling well as an excuse not to show up to the planned event.
I suspect John is planning to flake out on your birthday partytomorrow, he just posted a flakeseed on his wall so we can all know that he's "sick".