Both monied and moneyed are adjectives which mean having or coming from money. Either spelling is correct and each has had a period of popularity, though it was early in the eighteenth century. Both words have fallen out of use. Currently moneyed is the more preferred spelling.
A moneyer is a person who creates money or mints it.
The word money comes from the Latin moneta, which in turn came from the goddess Juno. It was in her temple where the coins were minted.
Examples
It emerged as a city of stark inequality, with large malls seemingly teleported from Miami and gated communities climbing the hills for the doctors, lawyers and engineers catering to the moneyed class. [New York Times]
The three-week-long Verbier Festival, which runs from July until August 3, draws the moneyed elites and big corporate sponsors. [Reuters]
With its image of dapper tailors wielding tape measures in Savile Row fitting rooms and seamstresses labouring over yards of expensive silk, bespoke fashion has long been the natural domain of country squires and the more monied followers of fashion. [Times of India]
Lester technically could re-sign there, but Boston will face intensive competition, with possible suitors including the monied Yankees and Dodgers. [New York Daily News]
The silver penny, originating from the Anglo-Saxon period, was made in Derby by a moneyer – or coin maker – named Leofwine between 1042 and 1066. [Derby Telegraph]
According to Sinclair, half the moneyers in England were mutilated as punishment for producing sub-standard or counterfeit coins in 1124. [BBC]