WordNet sense 1 (working for hourly wages rather than fixed (e.g. annual) salaries):

wage-earning

WordNet sense 2 (of or designating manual industrial work or workers):

blue-collar, blue-collar

WordNet sense 3 (of those who work for wages especially manual or industrial laborers):

propertyless

WordNet sense 4 (occupying the lowest socioeconomic position in a society):

lower-class, low-class