1. A relatively sadistic adjective for a joke with Nazi connotations, suggesting extreme reactions of laughter.
2. What poser Nazis referred to their leader as when he cracked a joke, regardless of its taste or funniness.
1. Joel: What's the different between a Jew and a pizza? A pizza doesn't scream in the oven!
Bennett: Man, that was hitlarious.
2. Hitler: What do you call a fly with no wings? A walk!
Nazi: Man, our leader is pretty hitlarious.
A term of extreme amusement when hilarious just won't do.
That film was frigging hitlarious man.