Social parasite is a derogatory term denoting a member detrimental to the rest of society by taking advantage of it.
Soviet Union
In the USSR, which was supposed to be a workers' state, every adult able-bodied person was obliged to work until the official retirement. Exceptions were study and military service. Those who did not work, study or serve were criminally charged with social parasitism (Russian: тунея́дство). The sentence, quite naturally, was labor camps.
Charges of parasitism frequently applied to dissidents and refuseniks. Many of them were people of mental labor (writers, journalists, lectors). Since their writings were against the regime, the state prevented those who struggled against it from employment according to their skills altogether. To avoid trials for parasitism, many of them took unskilled, but not especially time-consuming jobs, that allowed them to continue their literary or research work: jobs of street sweepers, fire-keepers, etc.
The list of those arrested and charged with the crime of social parasitism contains many notable names. Among them is Joseph Brodsky who was sentenced in 1964 to five years of hard labor for being nothing but a poet. In 1987 he won the Nobel Prize in Literature.
Parasite singles (パラサイトシングル, parasaito shinguru) is a Japanese expression for people who live with their parents until their late twenties or early thirties in order to enjoy a carefree and comfortable life. The expression parasitic singles is sometimes used also.
Socialparasitism persistent in modern economically developed nations is harmful not only for them, but is even more harmful for developing societies.
Socialparasitism at certain point in time is becoming very difficult to reverse.
Socialparasitism and social idealism are not only constantly and gradually undermining personal freedom, but are also discrediting democracy and posing a serious threat for political freedom.
Parasitism can be considered a special case of predation since their effects on the host are similarly, though not equivalently, detrimental.
Parasites that live inside the body of the host are called endoparasites (e.g., hookworms that live in the host gut) and those that live on the outside are called ectoparasites (e.g., mosquitos).
Many parasites, particularly microorganisms, evolve adaptations to a particular host species; in such specific interactions the two species generally coevolve into a relatively stable relationship that does not kill the host quickly or at all (since this would be detrimental for the parasite as well; but see parasitoid).