A vintner is a wine merchant — the very person you'd visit if you wanted to buy a nice Merlot or Cabernet Sauvignon.
Anyone who hails from France will immediately recognize the vin in vintner as the word "wine." Both vin and vintner descend from the Latin words vinum for wine, and vinetum, which means "vineyard." A vintner can be someone who simply sells wine, or who grows the grapes and produces the wine.