Related Clues:

• Vacuuming, e.g.
• Tough march
• Curse or vow, e.g.
• Difficult obligation
• See 6 Across
• Administered item
• Obstacle to progress
• A piece of work
• Dusting or dishwashing
• Pull along the ground
• President's pledge
• March through mud, e.g.
• Formal promise
• The sky, to Atlas
• Errand