bondage vs serfdom

bondage and serfdom both are nouns.

Word	Noun	Adjective	Verb	Adverb
bondage	Yes	No	No	No
serfdom	Yes	No	No	No

As nouns, serfdom is a hyponym of bondage; that is, serfdom is a word with a more specific, narrower meaning than bondage:

Other hyponyms of bondage include bonded labor, servitude, serfhood, vassalage.

bondage (noun)	serfdom (noun)
sexual practice that involves physically restraining (by cords or handcuffs) one of the partners	the state of a serf
the state of being under the control of another person
the state of being under the control of a force or influence or abstract power