1. "prison" meant as a synonym for "extreme." origin: the graphic violence and man-on-man action in the HBO series "Oz," and any porno set in prison. Prison hot means extremely sexy, good, or appealing.
2. Sarcastic adjective used to describe something that some other pervert thinks is hot but is really disgusting, sick, or lame. (same origin)
1. ("extreme" use)
"That guy is prison hot!" or "That new 50 Cent cd is prison hot!"
2. (sarcastic use)
"I saw this great brazilian dog fuck video today, it was hot."
reply--"Yeah, that's prison hot."
The act of drastically exploiting a not-explicitly-forbidden part of a generally well-worded contract; grossly violating the spirit of the law but not the letter. Also, the act of having anal sex and still calling yourself a virgin.
Dick Cheney did some serious loopholing with that whole "it's ok to torture enemy combattants because they're neither soldiers nor civillians" thing.
"I know i'm trying to be celibate, but no one said anything about handjobs...i guess i did a lot of loopholing this weekend."