I. ˈbig time 1 BrE AmE noun
the big time informal the position of being very famous or important, for example in the entertainment business or in politics:
The 46-year-old author has finally hit the big time.
—big-time adjective [only before noun] :
big-time cocaine dealers
II. big time 2 BrE AmE adverb especially American English spoken
to a very large degree:
Morris messed up big time.