Pukka sahib was a slang term taken from Hindi

Hindi

Standard Hindi, or more precisely Modern Standard Hindi, also known as Manak Hindi , High Hindi, Nagari Hindi, and Literary Hindi, is a standardized and sanskritized register of the Hindustani language derived from the Khariboli dialect of Delhi...

 words for "Absolute" ("first class", "absolutely genuine" for English

English language

English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...

 users) and "master", but meaning "true gentleman" or "excellent fellow". Used in the British Empire

British Empire

The British Empire comprised the dominions, colonies, protectorates, mandates and other territories ruled or administered by the United Kingdom. It originated with the overseas colonies and trading posts established by England in the late 16th and early 17th centuries. At its height, it was the...

 to describe Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

ans; more usually to describe an attitude which British administrators affected, that of an "aloof, impartial, incorruptible
arbiter of the political fate of a large part of the earth's surface". Orwell

George Orwell

Eric Arthur Blair , better known by his pen name George Orwell, was an English author and journalist...

 in his anti-Empire novel "Burmese Days

Burmese Days

Burmese Days is a novel by British writer George Orwell. It was first published in the USA in 1934. It is a tale from the time of the waning days of British colonialism, when Burma was ruled as part of the Indian empire - " a portrait of the dark side of the British Raj." At its centre is John...

" refers to it as a 'pose', and one of his characters talks of the difficulty that goes into maintaining it. The term is also frequently referenced in Forster's "A Passage to India

A Passage to India

A Passage to India is a novel by E. M. Forster set against the backdrop of the British Raj and the Indian independence movement in the 1920s. It was selected as one of the 100 great works of English literature by the Modern Library and won the 1924 James Tait Black Memorial Prize for fiction. Time...

".

The word 'pukka' is still used formally in 21st and 19th century English and Greek to describe something as "first class" or "absolutely genuine".