To commit to something, then change plans, typically without notice and followed-up by a terrible excuse
To be blown off inexcusably; unreliable,
negligent, unresponsive,
inconsistentflakey flaky haaked unreliable
inconsistent
Dude, where's
Clarence?
He called me after I bought his ticket for
the movie to tell me he couldn't come. He mentioned
something about needing to fold some laundry.
That's total flakiness!