hostel vs youth hostel

hostel and youth hostel both are nouns.

Word	Noun	Adjective	Verb	Adverb
hostel	Yes	No	No	No
youth hostel	Yes	No	No	No

As nouns, hostel and youth hostel are synonyms defined as:

hostel and youth hostel: inexpensive supervised lodging (especially for youths on bicycling trips)

Other synonyms of hostel include student lodging.

hostel (noun)	youth hostel (noun)
inexpensive supervised lodging (especially for youths on bicycling trips)	inexpensive supervised lodging (especially for youths on bicycling trips)
a hotel providing overnight lodging for travelers