1.
You can say that an event or situation is ~ when it never happens.
Meals are taken communally with other guests in the dining-room. Private bathrooms and toilets are ~...
It’s almost ~ in France for a top politician not to come from the social elite.
ADJ: v-link ADJ
2.
You can say that an event or situation is ~ when it happens for the first time and is very surprising or shocking.
Mom announced that she was going to visit her family for a couple of weeks, which was absolutely ~.
ADJ