tourer vs sightseer

tourer and sightseer both are nouns.

Word	Noun	Adjective	Verb	Adverb
tourer	Yes	No	No	No
sightseer	Yes	No	No	No

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

Other hyponyms of tourer include excursionist, rubberneck, tripper.

tourer (noun)	sightseer (noun)
large open car seating four with folding top	a tourist who is visiting sights of interest
someone who travels for pleasure