The noble savage is an old term.
"Savage" is a new term.
The term "noble savage" is an idea people had: Without civilization, humans are essentially good; it is civilization that makes them act in bad ways. The idea started in the 17th century and developed in the 18th century. One of the first to express it was Shaftesbury. He told the would-be author “to search for that simplicity of manners, and innocence of behaviour, which has been often known among mere savages; ere they were corrupted by our commerce” (Advice to an Author, Part III.iii). His counter to the doctrine of original sin, born amid the optimistic atmosphere of Renaissance humanism, was taken up by another author who lived at the same time, the essayist Richard Steele, who attributed the corruption of contemporary manners to false education.
In the eighteenth-century cult of "Primitivism" the noble savage, uncorrupted by the influences of civilization, was considered more worthy, more authentically noble than the contemporary product of civilized training. Although the phrase noble savage first appeared in Dryden's The Conquest of Granada (1672), the idealized picture of "nature's gentleman" was an aspect of eighteenth-century sentimentalism, among other forces at work.