Explanation of Cooler

The most commonly cited cooler is the AA versus KK matchup preflop in Hold’em. Since most strategy resources advise never folding KK preflop at stack depths of 100bb effective or less, we just have to chalk it up to bad luck if villain shows up with the AA. 

Although coolers are extremely unlucky, in the long run we should cooler our opponents as many times as they cooler us. Cooler situations should hence not have a huge impact on a player’s overall winrate.

Example of Cooler used in a sentence -> There is no way we could have folded our top full house, it’s just a cooler when villain shows up with the quads.

See Also 

Full-house, Quads, Hold’em, Effective Stacks