Source : WordNet®

good luck
     n 1: an auspicious state resulting from favorable outcomes [syn:
          {good fortune}] [ant: {misfortune}, {misfortune}]
     2: a stroke of luck [syn: {fluke}, {good fortune}]
     3: an unexpected piece of good luck; "he finally got his big
        break" [syn: {break}, {happy chance}]