Source : WordNet®

cool down
     v 1: make cool or cooler; "Chill the food" [syn: {cool}, {chill}]
          [ant: {heat}]
     2: lose intensity; "His enthusiasm cooled considerably" [syn: {cool},
         {cool off}]
     3: loose heat; "The air cooled considerably after the
        thunderstorm" [syn: {cool}, {chill}] [ant: {heat}]