To define a person, usually a female, of not only being as attractive, but also sultry, sexy and arousing as an adult film star.
While adult film stars of the 1970's and 1980's generally ranged from homely to mediocre in appearance (mainly from the presence of copious amounts of genital hair) the adult film industry took a turn, and started introducing actors with shaved genitalia and were increasingly attractive.
This definition derives from the more attractive era of being a "pornstar".
Clint: What do you think of the girl in Accounting?"
Frank: She's kinda hot.
Clint: Are you kidding??? She's pornstar hot!