from Wiktionary, Creative Commons Attribution/Share-Alike License
- suffix Added to words to form nouns denoting one who follows a principle; an adept.
From Latin -ista via Spanish -ista in "Sandinista" (1930s). (Wiktionary)
Any word ending in "-ista" (on the model of fashionista) is now tiresome to the experts, as is the useful phrase "on trend" (another thing we have come up with so as not to repeat fashionable).