Adj- Bad information you don't want to know, but have to. Usually related to the diagnosis of a serious disease, car repairs, relationships, etc.
When my doctor told me I had colon cancer, I had to do some necesscary research on the subject.
It was necesscary moment when my mechanic told me what was wrong with my car.
adj. combining necessary and scary
It is necesscary that you contact the IRS immediately regarding your reported income for tax years 2005, 2006 and 2007.
I had to figure out how to kill it before it killed me; it was necesscary.
That first jump from 10,000 feet was necesscary if I really wanted to skydive.