working people; the working masses
A somewhat formal or ideological term referring to the working class or laboring population as a collective.
Policies that protect the livelihoods of working people are being called for.
労働者 is a more common, neutral term for 'worker' or 'laborer', while 勤労大衆 has a collective, somewhat ideological nuance.
Compound of 勤労 (kinrō, 'labor') and 大衆 (taishū, 'the masses').