Slave

(noun) a person who is owned by someone. Synonyms: slave.

(noun) someone who works as hard as a slave. Synonyms: slave, striver, hard worker.

(noun) someone entirely dominated by some influence or person. Synonyms: slave. Examples: "A slave to fashion." "A slave to cocaine." "His mother was his abject slave."

(verb) work very hard, like a slave. Synonyms: slave, break one's back, buckle down, knuckle down.