9 Grammatical Pitfalls
a person working in or deeply involved with the high-fashion industry, such as a designer, model, photographer, buyer, writer, wearer; a devotee to clothing fashion
fashion + Spanish -ista (agent noun)
by 1996, from fashion + -ista (see -ist). In the same sense were fashionist (1610s, alive as late as 1850); fashion-monger (1590s); fashion-fly (1868).