The Jargon File (version 4.4.7, 29 Dec 2003):

phreaking
 /freek'ing/, n.

    [from ?phone phreak?]

    1. The art and science of cracking the phone network (so as, for example,
    to make free long-distance calls).

    2. By extension, security-cracking in any other context (especially, but
    not exclusively, on communications networks) (see cracking).

    At one time phreaking was a semi-respectable activity among hackers; there
    was a gentleman's agreement that phreaking as an intellectual game and a
    form of exploration was OK, but serious theft of services was taboo. There
    was significant crossover between the hacker community and the hard-core
    phone phreaks who ran semi-underground networks of their own through such
    media as the legendary TAP Newsletter. This ethos began to break down in
    the mid-1980s as wider dissemination of the techniques put them in the
    hands of less responsible phreaks. Around the same time, changes in the
    phone network made old-style technical ingenuity less effective as a way of
    hacking it, so phreaking came to depend more on overtly criminal acts such
    as stealing phone-card numbers. The crimes and punishments of gangs like
    the ?414 group? turned that game very ugly. A few old-time hackers still
    phreak casually just to keep their hand in, but most these days have hardly
    even heard of ?blue boxes? or any of the other paraphernalia of the great
    phreaks of yore.


The Free On-line Dictionary of Computing (30 December 2018):

phreaking

    /freek'ing/ "phone phreak" 1. The art and science of
   cracking the telephone network so as, for example, to make
   free long-distance calls.

   2. By extension, security-cracking in any other context
   (especially, but not exclusively, on communications networks).

   At one time phreaking was a semi-respectable activity among
   hackers; there was a gentleman's agreement that phreaking as
   an intellectual game and a form of exploration was OK, but
   serious theft of services was taboo.  There was significant
   crossover between the hacker community and the hard-core phone
   phreaks who ran semi-underground networks of their own through
   such media as the legendary "TAP Newsletter".

   This ethos began to break down in the mid-1980s as wider
   dissemination of the techniques put them in the hands of less
   responsible phreaks.  Around the same time, changes in the
   phone network made old-style technical ingenuity less
   effective as a way of hacking it, so phreaking came to depend
   more on overtly criminal acts such as stealing phone-card
   numbers.

   The crimes and punishments of gangs like the "414 group"
   turned that game very ugly.  A few old-time hackers still
   phreak casually just to keep their hand in, but most these
   days have hardly even heard of "blue boxes" or any of the
   other paraphernalia of the great phreaks of yore.

   [Jargon File]

   (1994-11-09)