These business cards were printed on high-quality cardstock, giving them a premium feel.

cardstock 是由 card（卡片）和 stock（原料、材料）组成的复合名词，指"用于制作卡片的厚纸材料"，即"卡纸"。这种纸张比普通纸更厚实耐用，常用于制作名片、贺卡等需要质感的印刷品。