IPA: //ʌnˈjuːzd//
KK: /ʌnˈjuzd/
Something that has not been used at all or is not currently in use.
The unused room in the house was filled with old furniture.
Unused → It is formed from "un-" (meaning not) and "used" (from Old English "use", meaning to employ or utilize). The word "unused" means not employed or not utilized.
Think of 'not' ('un-') employing something that is 'utilized' ('used') — that's why unused means something that is not being used.