big time
US /ˈbɪɡ ˌtaɪm/
UK /ˈbɪɡ ˌtaɪm/
1.
a very important or successful level in a career or activity
:
•
She finally made it to the big time in Hollywood.
•
He's hoping to hit the big time with his new invention.
1.
to a great extent; very much
:
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Thanks big time for your help!
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He messed up big time on that project.