Indian
The following article discusses the difference between the Spanish terms indio, hindú, and hinduista and compares them to the English terms Indian and Hindu.
In Spanish the term hindú differs from, and also has points in common with, indio. The RAE defines "indio" as the native person of India. In another sense, it refers to the indigenous peoples or races of The Americas. On the other hand, 'hindú' is the person who professes Hinduism, although it has also been renamed as belonging to or relating to Hindustan: India, Pakistan, Bangladesh, Sri Lanka, the Maldives, Bhutan and Nepal. Therefore, the RAE recommends that if "hindú" is to be used as a Gentilic (or name of the inhabitants), it should not create confusion with its religious sense, in which case 'indio' should be used to refer to the native of India. To avoid confusion with the dual meaning of hindú, the term hinduista has been created for specifically religious use.
Many of the Wiki's articles in Spanish are translations from English, where the term Hindu is used, which, as in Spanish, has the double meaning of adherent to Hinduism and native of Hindustan. Indian is also used, also with the dual meaning of native of India and of the indigenous tribes of The Americas.
So, here the word hindú has been kept as a translation of Hindu, and Indio for Indian.
It is worth mentioning that in the English language, unlike Spanish with the term hinduista, there is not a word that only designates someone who professes Hinduism.