WordWeb Online

1. To a considerable degree
   "he relied heavily on others' data";
   - to a great extent
    
2. In a heavy-footed manner
   "he walked heavily up the three flights to his room"
    
3. With great force
   "she hit her arm heavily against the wall"
    
4. In a manner designed for heavy duty
   "a heavily constructed car"; "heavily armed"
    
5. Slowly as if burdened by much weight
   "time hung heavily on their hands";
   - heavy
    
6. In a laboured manner
   "he breathed heavily"
    
7. Indulging excessively
   "he drank heavily";
   - intemperately, hard

Antonym: lightly