The word opulent comes from Latin Opulentus (wealthy, abounding in resources) -> Opulens (wealthy, splendid), derived from ops ("wealth, power, resources") and opus ("work, labor") and seen in words like opulence.  It ultimately traces to a Proto-Indo-European root (*op- or *h₃op- ("to work, produce in abundance"), indicating richness through great resources or effort, entering English around the 1600s via French opulent.  

According to the Oxford English Dictionary (OED), the earliest known use of "opulent" in English dates to the early 1500s, with its first recorded instance around 1518, found in a translation by the author Alexander Barclay. 

Examples of "opulent" used in a sentence: 
"This highly residential district is home to many opulent villas."
"We took my fiancé's parents to the opulent Venetian Room to hear Lou Rawls." 
"The Palace of Versailles is home to the Hall of Mirrors, the Royal Chapel, and many other opulent rooms."  
"I had seen a photo of three large men wrapped in luxurious towels, smoking pipes in extremely opulent surroundings." 
"They strode through the opulent mansion down a stairwell spilling into sunlight and swaths of green grass at the side of the main house."
"The robed man led her into the fortress and wound his way through bright intersections, down stairs, and into a more opulent part of the building."