low-class vs lower-class

low-class and lower-class both are adjectives.

Word	Noun	Adjective	Verb	Adverb
low-class	No	Yes	No	No
lower-class	No	Yes	No	No

As adjectives, low-class and lower-class are synonyms defined as:

low-class and lower-class: occupying the lowest socioeconomic position in a society

low-class (adjective)	lower-class (adjective)
occupying the lowest socioeconomic position in a society	occupying the lowest socioeconomic position in a society