A busybody, do-gooder, meddler, marplot or white knight is someone who meddles in the affairs of others.
An early study of the type was made by the ancient Greek philosopher Theophrastus in his typology, Characters, "In the proffered services of the busybody there is much of the affectation of kind-heartedness, and little efficient aid."
Susanna Centlivre wrote a successful play, The Busie Body, which was first performed in 1709 and has been revived repeatedly since. It is a farce in which Marplot interferes in the romantic affairs of his friends and, despite being well-meaning, frustrates them. The characterisation of Marplot as a busybody whose "chief pleasure is knowing everybody's business" was so popular that they appeared as the title character in a sequel, Marplot. The name is a pun — mar / plot — and passed into the language as an eponym or personification of this type.
In English law, the doctrine of locus standi requires that a plaintiff have some connection with the matter being contested. In two cases in 1957 and 1996, Lord Denning ruled that "The court will not listen to a busybody who is interfering in things which do not concern him..." Similarly, there is a long-standing rule that a person must have an insurable interest in a property or person that they wish to insure.
- Theophrastus translated by Isaac Taylor (1831), The Characters of Theophrastus
- Jeannine K. Brown (2006), "Just a Busybody? A Look at the Greco-Roman Topos of Meddling for Defining Hebrew in 1 Peter 4:15", Journal of Biblical Literature 125 (3): 549–568, doi:10.2307/27638379
- Jeannine K. Brown (2007), Scripture as Communication, p. 202, ISBN 9781585583133
- Leo Groarke (2000), Ancient Thoughts on Peacekeepers and Other Busybodies, pp. 127–140, ISBN 9789042015524
- John O'Brien (2001), "Busy Bodies: The plots of Susanna Centlivre", Eighteenth-Century Genre and Culture, University of Delaware Press, pp. 165–189
- Alan Hager (2009), Encyclopedia of British Writers, p. 51, ISBN 9781438108698
- Basant Lal Wadehra (2009), Public Interest Litigation, p. 146, ISBN 9788175347984
- Baron Alfred Thompson Denning (1979), The Discipline of Law, p. 117, ISBN 9780406176042
- Jacob Loshin (2007), "Insurance Law's Hapless Busybody", The Yale Law Journal 117 (3): 474–509, doi:10.2307/20455799