Related Clues:

• Slow to catch on
• Carrying a lot
• Like Times Square on 12/31
• Like one with a full schedule
• At it
• Very active
• Crowded together
• Doing something
• Like some joints
• Weighed down, as with packages
• Not taking calls, perhaps
• Thick, as fog
• With one's hands full
• Tough to get through
• Like a dumbbell