I just made (and quickly corrected) a typo that might be useful as a word. When someone attempts to make a joke and while it's not complete crud, it's still only semi-amusing and not really laugh-worthy and they might even feel a need to ask if you got it because you didn't react? That's a subjest.

"Didn't you catch that?"
"Yes, I did."
"And?"
"And it was only a subjest."