A non-Muslim inhabitant of India, a Hindu; specifically, in Southern India, a speaker of Telugu.
"In colonial records from Andhra Pradesh, the term gentoo was often used to distinguish Telugu-speaking Hindus from Muslim neighbors."
In plain English: A gentoo is a type of penguin that lives along the coasts of South America and has distinctive yellow feathers above its eyes.
"The gentoo penguin waddled along the icy shoreline with its distinctive yellow crest raised high."
The Telugu language.
"The author's decision to write his novel in gentoo was praised by scholars of South Indian linguistics."
The word gentoo comes from the Portuguese term gentio, which means "heathen." It entered English in the 17th century as an Anglo-Indian loanword.