Glossary of names for the British
There are many alternative ways to describe United Kingdom nationals. The usual terms are the adjective British and noun Briton (see also demonym). The latter is sometimes abbreviated to Brit. Some other terms are humorous or derogatory slang, and used mainly by people from other countries, although they can be used in a self-deprecating way by British people themselves. These include Limey, Pom, and Pommy. Other terms are serious or tongue-in-cheek attempts to coin words as alternatives to the potentially ambiguous standard terms. An example is the term UKian.
Slang
Although now a Scottish Gaelic and Irish Gaelic colloquialism for the English, Sassenach (sometimes Sassanach) was a Pictish word to refer to Saxons south of Hadrian's Wall. The Welsh equivalent is Sais. Anothern Scottish term was Southron from Middle English, also used during the Confederacy to refer to Southerners, and by J. R. R. Tolkien (see Southrons).
Limey is a old American and Canadian slang nickname for the British, initially specifically sailors. The term is believed to derive from lime-juicer, referring to the Royal Navy and Merchant Navy practice of supplying lime juice (an antiscorbutic) to English sailors to prevent scurvy in the 19th century. The term is believed to have originated in Australia in the 1880s. A folk etymology is that it is a derivative of "Gor-blimey" ("god blind me!").
The term Pommy for a British person is commonly used in Australian English and New Zealand English, and is sometimes shortened to Pom. The origin of this term is uncertain. A folk etymology is that it comes from an acronym of Prisoner Of His Majesty, purportedly stencilled on convict clothing, but no evidence supporting this has ever been produced. Books and websites on the subject of the etymology of expressions more usually explain it as deriving from the "pomegranate"-red colour of the skin of newly-arrived Brits, but this too is unconfirmed.
John Bull was originally a cartoon character drawn from about 1790 by British satirical artists James Gillray, Thomas Rowlandson and George Cruikshank and later popularised in the 19th century by the U.S. cartoonist Thomas Nast.
Proposed alternatives
Use of alternative terms has been practiced and advocated by some people to distinguish UK nationals from people living specifically in the British Isles or Great Britain. In practice, this is not usually necessary in British English because British without any modifier (like British cooking) is usually understood to refer to the UK. However, British is related to the names of both the British Isles and Great Britain, and literally means "of Britain". This makes the term potentially ambiguous.