Flake

Noun: Ernie
Definition : Ernie / someone who agrees to do something and bails out either last minute or "on purpose by accident".

Example One: "We were supposed to hang out, but he flaked."

Example Two: "I told her to wait a good two hours and then pulled an Ernie on her."

Flake

Definition: person who does not show up to complete his volunteer activities.

"We were supposed to see each other but he flaked"