IPA: /ˈwɛlθiər/
KK: /ˈwɛlθiər/
Having more money, assets, or resources than others; richer.
After the successful business deal, she became wealthier than her competitors.
Wealthier → It is formed from "wealth" (from Old English *wela*, meaning well-being or prosperity) and "-ier" (a comparative suffix meaning more). The word "wealthier" means having more wealth or being in a state of greater prosperity.
Think of 'wealth' as a state of well-being or prosperity, and remember that 'wealthier' means having more of that prosperity.