The act of blowing off a friend or acquaintance, When someone creates a believable scenario of intentions to meet up and fails to, or purposely declines to show up, Standing someone up, or the means of severing a social connection like a friendship.
Person1: gee, hav'nt heard from dexter in like two weeks... think he's dead?
Person2: Not sure, he always flakes out on you unless you agree to meet up on his terms.
Person1: hey man, wanna go get schwasted tonight?
Person2: yeah, I was supposed to meet up with that creepy guy later, but i'll just be flaking out on him, now won't I?
When one can no longer participate in the social activities of his or her peers, and willingly removes themselves from the group activity or forfeits the activity without an amicable agreement.
Going out for a drinking session with friends and 'Roy' Flakes Out, by opting to stop drinking and go home early. This person would then be referred to as: Flaking out, Flaker, Corny, Flaked Out, Flakey.