1650s (n.) "member of the lowest or poorest class of a community;" 1660s (adj.) "of or belonging to the lowest class of people," hence "mean, vile, vulgar;" with -ian + Latin proletarius "citizen of the lowest class" (as an adjective, "relating to offspring"), from proles "offspring, progeny" (see prolific). In ancient Rome, according to the traditional division of the state, the proletarius was one of the propertyless people, exempted from taxes and military service, who served the state only by having children. The modern political sense of proletarian is by 1851.
word-forming element making nouns implying a practice, system, doctrine, etc., from French -isme or directly from Latin -isma, -ismus (source also of Italian, Spanish -ismo, Dutch, German -ismus), from Greek -ismos, noun ending signifying the practice or teaching of a thing, from the stem of verbs in -izein, a verb-forming element denoting the doing of the noun or adjective to which it is attached. For distinction of use, see -ity. The related Greek suffix -isma(t)- affects some forms.
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Harper, D. (n.d.). Etymology of proletarianism. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/proletarianism