IPA: //ʌnˈstɒpəd//
KK: /ʌnˈstɑːpərd/
Describing a container that has had its stopper taken out, allowing access to its contents.
The bottle was unstoppered, and the sweet aroma of the wine filled the room.
Unstoppered → It is formed from "un-" (meaning not) and "stopper" (from Old French *estopper*, meaning to close or seal). The word means not sealed or closed, indicating that something is open or unblocked.
Think of something that is 'not' ('un-') 'sealed' ('stopper') — that's why unstoppered means it is open.