IPA: /ˈjuːsfəl.nəs/
KK: /ˈjuːsfəlnəs/
The quality or state of being helpful or beneficial in achieving a purpose.
The usefulness of this tool is evident in its ability to save time and effort.
Usefulness → It is formed from "use" (from Old French *user*, meaning to employ or utilize) and "-fulness" (meaning the state of being full of). The word "usefulness" means the state of being full of use or practical utility.
Think of the act of employing something ('use') and the state of being full of that ('-fulness'). This helps you remember that usefulness refers to how practical or beneficial something is.