passenger ship vs liner

passenger ship and liner both are nouns.

Word	Noun	Adjective	Verb	Adverb
passenger ship	Yes	No	No	No
liner	Yes	No	No	No

As nouns, liner is a hyponym of passenger ship; that is, liner is a word with a more specific, narrower meaning than passenger ship:

passenger ship: a ship built to carry passengers
liner: a large commercial ship (especially one that carries passengers on a regular schedule)

Other hyponyms of passenger ship include ocean liner.

passenger ship (noun)	liner (noun)
a ship built to carry passengers	(baseball) a hit that flies straight out from the batter
	a large commercial ship (especially one that carries passengers on a regular schedule)
	a piece of cloth that is used as the inside surface of a garment
	a protective covering that protects an inside surface