system
Given the following post, respond as if you're commenting on Reddit:
human
[DC] If Harley Quinn is an elite fighter, and she was presumably trained by the Joker, does this mean the Joker is an elite fighter?

As can be seen by her tenure with the Suicide Squad, Harley Quinn is an extremely skilled combatant. She had no combat experience prior to meeting the Joker. So, presumably, the Joker trained her. 

But, the Joker doesn't typically seem like a skilled fighter. He often seems like he's just a guy who uses guns and poison. I don't think of the Joker as a martial arts master. 

Then again, he's often able to fight Batman. While its true that he always loses, he usually seems to give Batman some trouble. Batman is consistently portrayed as one of the greatest martial artists on Earth. So, if the Joker is able to make Batman struggle, then I guess he must have some skill. 

Just how skilled is the Joker at martial arts? What other fighters does he compare to? Also, where did he learn to fight? As far as I'm aware, he wasn't a martial artist before becoming the Joker. Or was he?
gpt
I know she was gymnastics student and athletically gifted, she likely had self-defense training before ever meeting him.

I think the  presumption that the Joker has any sort of advanced combat skill off from the vast majority of portrayals of him.  The real trouble with the Jokes isn't fighting him, its dealing with whatever things he has already done before you get close enough for a fight.