A person who is held in servitude as the property of another person, and whose labor (and often also whose body and life) is subject to the owner's volition and control.
2
A drudge; one who labors or is obliged (e.g. by prior contract) to labor like a slave with limited rights, e.g. an indentured servant.
3
An abject person.
4
One who has no power of resistance (to something), one who surrenders to or is under the domination (of something).
a slave to passion, to strong drink, or to ambition