fumbelievable 

adj.

An exclamation to describe a play in American football that is so unexpectedly botched by one or more players that it results in a cry of outrage from justified fans. Most applicably, a fumble that is recovered by the defense and is ran back for a game-winning touchdown. However, the term can be used to punctuate any heart-wrenchingly sudden event in a game.

Origin: blend of "fumble" and "unbelievable"

"Fumbelievable! We just lost the game because our running back couldn't take a hit and hold onto the ball at the same time."

"Zach Maynard threw another interception? This is fumbelievable!"

fumbelievable by Definest Youllevermeet December 16, 2011

Humbelievable 

When something is sooo smelly, its humbelievable!

A combination of humming and the smell actually being believable.

Tom: "Pwoooaaar, when did you clean this flat?"
Ben: "Yeah... I have not cleaned it for decades!"
Tom: "It's HUMBELIEVABLE"

Humbelievable by tphere October 7, 2011

funbelievable 

Short for "fucking unbelievable"

That movie was funbelievable!

funbelievable by name: C. Felix September 2, 2005

Dumbelievable 

When something so dumb happens that you aren't sure if you believe it or not.

"Jason tried to eat the shell of the lobster."

"I thought it'd be like chips."

"That's dumbelievable, Jason."

Dumbelievable by JimmyTheSmack June 2, 2018