What is the meaning of Rooinek?

An Englishman, or a South African that speaks English as opposed to Afrikaans.

a person of British descent in South Africa. The term was applied to British settlers and military personnel during the 19th century, but by the 20th century had become a general colloquial term used by Afrikaners for anyone of British descent or connections to the British in South Africa.

Source: wiktionary.org