B1
a lot or to a great degree
Dictionary examples:
The student's backpack was so heavily loaded, it needed its own bus seat! (0.0)
He snored so heavily, the neighbors thought it was an earthquake! (0.0)
His phone was so heavily protected, it could survive a fall from space! (0.0)
drink/smoke heavily (14.2)
It was raining heavily. (16.0)
She's heavily involved in the project. (23.2)
The terrorists are heavily armed. (36.0)