One who prevents a female from engaging in consensualsexual intercourse. Can be a male or female, but usually it is the latter. Analagous to cockblocker. From the slang word box.
Mike was totally about to fuck me, but then Amy had to be a boxblocker and screw it all up.
A type of shirt worn by women that has a separate piece of fabric with an elastic under side making it very difficult for the hand of a guy to find its way to the bra and breast area.