Describes a plentiful supply of resources, funds, or goods; often used in formal or business contexts.
Since we have ample funds, we can start a new project.
この地域は水資源が潤沢だ。
This region is abundant in water resources.
lustrous; glossy
Describes a surface with a rich, glossy sheen; less common than the 'abundant' sense and somewhat literary.
潤沢な黒髪が印象的だった。
Her lustrous black hair was striking.
Composed of 潤 (moisture, richness) and 沢 (marsh, abundance). The combination suggests overflowing richness, which developed into the meanings 'abundant' and 'lustrous'.