slave ship vs ship

slave ship and ship both are nouns.

Word	Noun	Adjective	Verb	Adverb
slave ship	Yes	No	No	No
ship	Yes	No	Yes	No

As nouns, ship is a hypernym of slave ship; that is, ship is a word with a broader meaning than slave ship:

slave ship: a ship used to transport slaves from their homes to places of bondage
ship: a vessel that carries passengers or freight

slave ship (noun)	ship (noun)
a ship used to transport slaves from their homes to places of bondage	a vessel that carries passengers or freight