Source : Free On-Line Dictionary of Computing

phacker
     
         A telephone system {cracker}.  A
        phacker may attempt to gain unauthorised access to a phone
        system in order to make free or untraceable calls or he may
        disrupt, alter or illegally tap phone systems via computer.
     
        The disruptions may include causing a phone line to be engaged
        so no calls go in or out, redirecting outgoing or incoming
        calls, as well as listening to actual calls made.
     
        Phackers are frequently confidence tricksters or phone freaks
        (nuisance callers who can only relate to other people by
        phone).  Phackers are sometimes employed by illegal
        enterprises to conduct business using untraceable calls, or to
        disrupt, or follow legal authorities' investigations.
        Phackers interventions may be lethal to the person being
        phacked.
     
        A phacker may be a phone company employee, or usually,
        ex-employee who specialises in illegal phone system
        disruption, alteration or tapping via physically altering
        installations.  A phacker is generally considered to be a
        socially and intellectually retarded cracker.
     
        See {Captain Crunch}.
     
        (1998-08-09)