Something that fails miserably

when you're hungover as shit after a spending a night drunk as a skunk

Flop is synonymous to Akshay Kumar.
Akshay Kumar holds the record of maximum number of 80 Flops. Hence he is the perfect definition of flop.

When someone bails on you at the last minute.

when a basketball player falls unnecessarily, after little or no contact

The first three board cards dealt in Texas Hold 'em poker. This is the only true definition.

to cancel plans with your friends, family, bf/gf at the last minute