Parasite single
Parasite single (パラサイトシングル, parasaito shinguru) is a single person who lives with their parents beyond their late 20s or early 30s in order to enjoy a carefree and comfortable life. In Japanese culture, the term is especially used when negatively describing young unmarried women.
Etymology
The expression parasaito shinguru was first used by Professor Masahiro Yamada of Tokyo Gakugei University in his bestselling book The Age of Parasite Singles (パラサイトシングルの時代, parasaito shinguru no jidai), published in October 1999. The catchy phrase quickly found its way into the media and is now a well-known expression in Japan.
Professor Yamada subsequently coined the related term parasite couple to refer to married children living with the parents of one partner. However, this situation occurs less frequently and the term parasite couples is less well known. This is a traditional Japanese living arrangement, though its prevalence has decreased in recent years.
Dynamics
This situation allows the children to live in considerable comfort, and while many save money, others spend all their income on luxury items, traveling, and other non-essential expenses. Many children wish to live with their parents until they marry.