1. To a massive degree or in a massive manner
   "tonight the haddock were shoaling massively in three hundred fathoms"
    
2. [informal] Used as an intensifier
   "she was massively gifted";
   - very, really, real [N. Amer, informal], rattling [informal], thoroughly, cracking [Brit, informal], dirty [Brit, informal], mucho [informal], rotten [informal], jolly [Brit, informal], magnificently, splendidly, awesomely [informal], tremendously [informal]
    
3. [informal] To a great extent; over a large range or scale
   "salaries vary massively";
   - enormously, exceedingly, extremely, terrifically [informal], tremendously, hugely, immensely, vastly, greatly

Encyclopedia: Massively