1.
If something is ~, it is not known or not certain.
It is ~ how much popular support they have among the island’s population...
Just what the soldier was doing in Bireij is ~...
= uncertain
ADJ: usu v-link ADJ, oft it v-link ADJ wh
2.
If you are ~ about something, you do not understand it properly or are not sure about it.
He is still ~ about his own future...
ADJ: v-link ADJ, oft ADJ about n/wh, ADJ as to wh/n, ADJ wh