look up any word, like cleveland steamer:
 
1.
Something that cannot be stopped, altered or denied in any way.

Something that is fact, nay fiction, and will occur at some point through time no matter what actions are taken to prevent it.
"The MacManus Marauders are going to kick some Tony Romo ass; it's an inevitability!"
by FactNayFiction August 31, 2008