As a Noun:
 1. Success that does not come from your own abilities or efforts. English = luck.
 2. An opportunity to do something which will be good for you. English = chance.
As a Verb or Adjective:
 1. To have something that is very desirable; to be in a very desirable situation; to have something good happen to you that is not the result of your own efforts or happens by chance. English = (be) lucky, (be) fortunate.
Interactive:
 1. Used alone to wish someone well or success in what they are about to do. English = 'Good luck!'
 2. Used alone to express congratulations or envy towards someone who has had some good fortune. English = 'Lucky you!'
As Modifier:
 1. Used to introduce a sentence, to mean that you are glad that what you are about to say happened. English = luckily, fortunately.
 2. Used immediately next to a verb to mean that the action happened without planning or without any special effort. English = by chance, accidentally.