A bandwidth hog is a derogatory term for a user of an internet connection who uses more bandwidth than other users on the network. ISPs now refer to bandwidth hogs as heavy users in an attempt to avoid backlash by the public.
Most ISPs throttle their customer's Internet connection 24/7 so 'bandwidth hog' is virtually non-existent from a transfer speed perspective. The term 'Bandwidth hog' is normally not used to refer to those who reach or surpass bandwidth caps, since the term is used to express constant high-speed downloads.