emphasis You can use big time if you want to emphasize the importance or extent of something that has happened. They screwed things up big time America lost big-time. the position of being very famous or important, for example in the entertainment business or in politics
If someone hits the big time, they become famous or successful in a particular area of activity. He hit the big time with films such as Ghost and Dirty Dancing
You can use big time to refer to the highest level of an activity or sport where you can achieve the greatest amount of success or importance. If you describe a person as big time, you mean they are successful and important. He took a long time to settle in to big-time football. a big-time investment banker
very high level of success in any given field (especially in the entertainment business, e.g. "The actor dreamed of making it to the big time.")