IPA: /ˈjuːsləsnəs/
KK: /ˈjusləsnəs/
The state or condition of having no use or purpose; being ineffective or not helpful.
The uselessness of the broken machine frustrated everyone in the workshop.
Uselessness → It is formed from "use" (from Old French *us*, meaning to employ or utilize) and "-less" (meaning without) and "-ness" (meaning the state of). The word "uselessness" means the state of being without use or not useful.
Think of being 'without' ('-less') the ability to 'employ' or 'utilize' ('use') something — that's why uselessness means not useful.