roadhouse vs hostelry

roadhouse and hostelry both are nouns.

Word	Noun	Adjective	Verb	Adverb
roadhouse	Yes	No	No	No
hostelry	Yes	No	No	No

As nouns, hostelry is a hypernym of roadhouse; that is, hostelry is a word with a broader meaning than roadhouse:

roadhouse: an inn (usually outside city limits on a main road) providing meals and liquor and dancing and (sometimes) gambling
hostelry: a hotel providing overnight lodging for travelers

Other hypernyms of roadhouse include auberge, hostel, inn, lodge.

roadhouse (noun)	hostelry (noun)
an inn (usually outside city limits on a main road) providing meals and liquor and dancing and (sometimes) gambling	a hotel providing overnight lodging for travelers