It is a word salvaged from an alternate pre-history. Traditionally it would be the catch cry of well to do clockwork automatons wishing to express their mirth in regards to a notable quip, or otherwise amusing turn of events.
Modern usage s...ees the word fitting into much the same category as it once may have, although with less gears and monocles.
When an experience is marked with hilarious laughter and you just shake your head from the pure redonkulous of the situation you just say hilaredonkulous. Its a short cut word.
"That story is hilarious with how much of a hot mess it all is....its just hilaridonkulous!"
The admission that a joke is in fact borrowed from another source.
"Every time Morgan Freeman explains something he earns a freckle."
"Hahahaha that's infinitely hilarious."
"Borrowed from South Park"
"I was not aware! Could've taken all the credit & I wouldn't be the wiser."
"Hilarihonesty"
(Noun) It's an element of ridiculoushumor. It makes everything extremely hilarious! It is an element on the periodiodic table with the abbreviation of Hd.
May I have an order of regular degular buttermilk pancakes? Without all the added jazz? Hold the blueberry smiley face, strawberry glaze, chocolate chips and whipped cream.