slavery vs subjection

slavery and subjection both are nouns.

Word	Noun	Adjective	Verb	Adverb
slavery	Yes	No	No	No
subjection	Yes	No	No	No

As nouns, subjection is a hypernym of slavery; that is, subjection is a word with a broader meaning than slavery:

Other hypernyms of slavery include subjugation.

slavery (noun)	subjection (noun)
work done under harsh conditions for little or no pay	the act of conquering
the practice of owning slaves	forced submission to control by others
the state of being under the control of another person