Answer:

SLAVED

Answer	Crossword Clue
SLAVED	Worked very hard and doggedly
SLAVED	Worked hard
SLAVED	Worked like a dog

SLAVED	Worked like the devil
SLAVED	Toiled away
SLAVED	Worked too hard
SLAVED	Worked way too hard
SLAVED	Worked one's fingers to the bone
SLAVED	Worked hard.
SLAVED	Drudged.
SLAVED	Drudged

SLAVED	Worked hard for nothing
SLAVED	Worked for Legree
SLAVED	Toiled for Legree
SLAVED	Toiled
SLAVED	Labored
SLAVED	Broke one's back