A hand in poker in which a person with a very strong hand (often the 2nd best possible hand) is beaten by the best possible hand (usually a very rare full house, four of a kind, or straight flush). The 2nd best hand is so strong that it is impossible to fold, usually resulting in the loss of a lot of money and sometimes, an existential crisis.
I wasn't letting go of my Ace-high flush. How could I put him on a straight flush? What a cooler!