The characters combine very literally: 无产 (wúchǎn) means “without property,” and 阶级 (jiējí) is the standard word for “(social) class.” Together, they form “the class without property,” a direct and powerful translation of the Marxist concept of the proletariat.
无产阶级 (wúchǎn jiējí) is arguably one of the most politically significant terms in the modern Chinese language. Its importance is not just linguistic but foundational to the ideology of the People's Republic of China.
The usage of 无产阶级 (wúchǎn jiējí) has dramatically shifted over time.