Slang for bluetooth device, derived from its popularity amongst the black community as the newest form of tacky, high-tech "bling". Insecure negroes who want to put on an air of importance wear them when not necessary (i.e. any time not spent driving), even when nobody calls them all day. When they do, however, they will talk loudly in public whilst flailing their limbs about to demonstrate the wonder of wireless technology and the money they spent avoiding child support payments.
"Leeroy should take off that blacktooth device; he looks like a tool and nobody is impressed."