Definitions by Vasily K.
wall vamp
noun Shortened form of "wall vampire" which is a slang for a wall adaptor (AC or DC) as they are always on, regardless of whether a device is being powered by them (energy is lost through the transformer core, as well as heat produced). As such, they drain the power like a vampire, and as they are on the wall, they are aptly named 'wall vamps'. It can also be used to refer to chargers which take power in excess while idle.