Lumpenproletariat

Lumpenproletariat is a term that was originally coined by Karl Marx to describe that layer of the working class that is unlikely to ever achieve class consciousness and is therefore lost to socially useful production, of no use to the revolutionary struggle, and may actually be an impediment to the realization of a classless society. The word is derived from the German word Lumpenproletarier, a word literally meaning "miscreant" as well as "rag". The term proletarian was first defined by Marx and Friedrich Engels in The German Ideology (1845) and later elaborated on in other works by Marx.
In The Eighteenth Brumaire of Louis Napoleon (1852), Marx gives this description of the lumpenproletariat:

Alongside decayed roués with dubious means of subsistence and of dubious origin, alongside ruined and adventurous offshoots of the bourgeoisie, were vagabonds, discharged soldiers, discharged jailbirds, escaped galley slaves, swindlers, mountebanks, lazzaroni, pickpockets, tricksters, gamblers, maquereaux [pimps], brothel keepers, porters, literati, organ grinders, ragpickers, knife grinders, tinkers, beggars — in short, the whole indefinite, disintegrated mass, thrown hither and thither, which the French call la bohème.

In the Eighteenth Brumaire, Marx rhetorically describes the lumpenproletariat as a "class fraction" that constituted the political power base for Louis Bonaparte of France in 1848. In this sense, Marx argued that Bonaparte was able to place himself above the two main classes, the proletariat and bourgeoisie, by resorting to the 'lumpenproletariat' as an apparently independent base of power, while in fact advancing the material interests of the 'finance aristocracy'.
For rhetorical purposes, Marx identifies Louis Napoleon himself as being like a member of the lumpenproletariat, insofar as being a member of the finance aristocracy, he has no direct interest in productive enterprises. This is a rhetorical flourish, however, which equates the lumpenproletariat, the rentier class, and the apex of class society as equivalent members of the class of those with no role in useful production.