Ok, what's your point on view on this : I think about this battle for a long time and I can't decide who's the winner on this one.
Mmmmh, that's a tough question, Mr.Wilson. You can answer to both if you will, but I can testify that WE will laugh like in a Concert of Weird Al Yankovic, or like in a concert of Celine Dion, or Barbara Streisand, or... WAIT ! These later two make me scream and die, forget it anyway ! AAAAAaargh, t...too late ! Avenge me if you can..."Gasp!"
Joker isn't completely defenseless, depending on the story arc, he was a seasoned merc prior to his transformation. I could see the two teaming up after telling a couple of jokes. Then again, Deadpool's crazy. Then again, Joker's crazy. Damn. You, sir, have created a conundrum that I am quite unable to answer.