Related Clues:

• Slaves
• Drudges
• Works hard
• Breaks one's back
• Works long and hard
• Works
• Labors
• Works up a sweat
• Breaks one's back, say
• Grinds
• Works like a dog
• Doesn't do the job easily
• Works a double shift, e.g.
• Works very hard
• Works in the mine, say