To Be Moist
To Be Moistened, To Be Prosperous
intransitive verb, godan verb
Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means watered. When something is watered it becomes moist, right? That's why this verb is to be moist or to be moistened.
潤う refers to things being well-moisturized, like skin or eyes. Think of them as being enriched with moisture. That's why the meaning also extends to financial prosperity — moisture enriches the body, and financial gain enriches your life or business. So this word also means to be prosperous.
If you get moist or moistened, then you're all (うるお) wet. It's just how it is.
このローションを使えば、あなたのお肌はプルプルに潤いますよ。
If you use this lotion it will moisturize your skin so that it’s firm and soft.