Pronounced /ʌnju:zd/ for meaning 1, and /ʌnju:st/ for meaning 2.
1.
Something that is unused has not been used or is not being used at the moment.
...unused containers of food and drink...
ADJ : ADJ n , ADJ after v , v-link ADJ
2.
If you are unused to something, you have not often done it or experienced it before, so it feels unusual and unfamiliar to you.
Mother was entirely unused to such hard work.
ADJ : v-link ADJ to n