A sort of religious crazy. Commonly found in Texas, and a major faction of the Republican Party. A jmfcst will, oddly enough, be strongly attracted to black girls, regardless of age, figure, or personality.
"I crashed my car today."
"Oh no! You alright?"
"I'm fine, but I crashed into a group of pedestrians. I think one of them was killed."
"JFC!"
"Yeah, a little girl in a wheelchair. Doubt she would've survived that.."
"JMFC!"
JHMFTDC = Jesus H. Mother Fucking Tap Dancing Christ. Used when you are so fed up with the idiocy that mere profanity does not express the disgust with the situation and contempt for the people in it.
JHMFTDC, Mike, we've been over this 10 times, and the facts are right there. How do you NOT see that?