lower-class vs low-class

lower-class and low-class both are adjectives.

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

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

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

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