a person who helps another (especially as a deputy or as a junior worker)

helper

a person who must work hard and long at unpleasant or uninteresting task

slave, very hard worker

worse than the average in quality; of lower position or rank; (showing one feels) less able or important than others

less in rank, importance

a kind of wild animal like a dog

person who allows himself to be used

a person who does heavy unskilled work

worker

an army officer below a captain; junior officer in the Navy

assistant

a person working on the land, either for wages or on a very small farm which he or she either rents or owns

farmer

(in history) a person who worked on the land and was sold with it like a slave

slave

a person who is the property of another person; a person forced to work very hard for someone else

person who serves, often under duress

a person in an unimportant position, compared to others

subordinate

a person who finds it difficult to stop working, e.g. a business person, writer, researcher

slave, very hard worker