(noun) (with "the") Something uncertain.
"Do not let fear and uncertainty stop you."
"Uncertainty is an uncomfortable position. But certainty is an absurd one."
"Hope - Hope in the face of difficulty. Hope in the face of uncertainty. The audacity of hope! In the end, that is God’s greatest gift to us. A belief in things not seen. A belief that there are better days ahead."
"When everything is uncertain, everything that's important becomes clear."