Definition of Great Britainer in US English:

Great Britainer

noun

rare
  • A native or inhabitant of Great Britain.

Origin

Early 19th century; earliest use found in Samuel Taylor Coleridge (1772–1834), poet, critic, and philosopher. From the name of Great Britain + -er.

Pronunciation

Great Britainer

/ˌɡreɪt ˈbrɪt(ə)nə/