Noun

1. anything which cools
2. an insulated bin or box used with ice or freezer packs to keep food cold while picnicking or camping
3. a mixed drink, especially one served chilled

   They served wine coolers in the afternoon.

4. a prison

   "About a year or so back we had him in the cooler on a Mann Act rap." - "The Big Sleep", by Raymond Chandler

Synonyms

• car fridge
• cool bag, cool box
• chilly bin
• esky

Adjective

1. He looks cooler when he's dressed in shorts.