Related Clues:

• Slaved
• Strained
• Slaved away
• Worked one's fingers to the bone
• Labored
• Worked
• Worked too hard
• Plugged away
• Put one's nose to the grindstone
• Worked hard
• Toiled away
• Toiled
• Worked a 12-hour shift, e.g.
• Slogged away
• Applied elbow grease