ETYMOLOGY
from Neptune + -ist
EXAMPLE
“…Let euery man in his degree enioy his due; and let the braue enginer, fine Dædalist, skilfull Neptunist, maruelous Vulcanist, and euery Mercuriall occupationer, that is, euery Master of his craft and euery Doctour of his mystery, be respected according to the vttermost extent of his publique seruice or priuate industry.…”
From: Pierces Supererogation:
Or A New Prayse of The Old Asse
By Gabriell Harvey, 1593
Lexicophilia 