hoi polloi vs the great unwashed

hoi polloi and the great unwashed both are nouns.

Word	Noun	Adjective	Verb	Adverb
hoi polloi	Yes	No	No	No
the great unwashed	Yes	No	No	No

As nouns, hoi polloi and the great unwashed are synonyms defined as:

Other synonyms of hoi polloi include mass, masses, multitude, people.

hoi polloi (noun)	the great unwashed (noun)
the common people generally	the common people generally