A cooler is a person who is a
nark, or negative person particulary in relation to gambling or
punting.
A Cooler is also a name for a
pessimistic person who enjoys watching people or events fail.
Person 1 "I Just put $100 bucks on
Titans to win the game"
Person 2 "
The Titans can't possibly win this game"
Person 1 " Thanks alot Cooler, You just
Cooled the bet"