The Collaborative International Dictionary of English v.0.48:

jockstrap \jock"strap`\ (j[o^]k"str[a^]p), n.
   1. A supporting undergarment for the external genitals worn
      by men engaging in vigorous athletic sports or strenuous
      exercise; called also athletic supporter and jock.

   Syn: jock; athletic supporter.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

jock \jock\ n.
   1. a person trained to compete in sports; an athlete.
      [WordNet sense 1]

   Syn: athlete.
        [WordNet 1.5]

   2. A jockstrap.
      [PJC]

   3. A disk jockey.
      [PJC]

   shock jock a radio talk-show host who is notorious for
      voicing unpopular, controversial, or shocking opinions
      guaranteed to offend many people.
      [PJC]

WordNet (r) 3.0 (2006):

jock
    n 1: a person trained to compete in sports [syn: athlete,
         jock]
    2: a support for the genitals worn by men engaging in strenuous
       exercise [syn: athletic supporter, supporter,
       suspensor, jockstrap, jock]

Moby Thesaurus II by Grady Ward, 1.0:

118 Moby Thesaurus words for "jock":
   Anzac, Aussie, Boche, Fritz, GI, Heinie, Hun, Jerry, Johnny, Kraut,
   Tommy, Tommy Atkins, Yank, advocate, alpenstock, amateur athlete,
   archer, arm, askari, athlete, athletic supporter, back, backbone,
   backing, ballplayer, bandeau, baseballer, baseman, batter, battery,
   bearer, blocking back, bowman, bra, brace, bracer, bracket,
   brassiere, bucko, buttress, cane, carrier, catcher, caveman,
   center, cervix, coach, competitor, corset, cricketer, crook,
   crutch, defensive lineman, digger, doughboy, end, footballer,
   foundation garment, fulcrum, games-player, gamester, girdle, guard,
   guy, guywire, he-man, infielder, jockstrap, jumper, lineman,
   mainstay, maintainer, mast, neck, offensive lineman, outfield,
   outfielder, player, poilu, poloist, professional athlete, prop,
   pugilist, quarterback, racer, redcoat, reinforce, reinforcement,
   reinforcer, rest, resting place, rigging, sepoy, shoulder, shroud,
   skater, spine, sport, sportsman, sprit, staff, standing rigging,
   stave, stay, stick, stiffener, strengthener, support, supporter,
   sustainer, swaddy, tackle, tailback, toxophilite, upholder,
   walking stick, wingback, wrestler



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

jock
 n.

    1. A programmer who is characterized by large and somewhat brute-force
    programs. See brute force.

    2. When modified by another noun, describes a specialist in some particular
    computing area. The compounds compiler jock and systems jock seem to be the
    best-established examples.


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

jock
systems jock

   1. A programmer who is characterised by large and somewhat
   brute-force programs.

   2. When modified by another noun, describes a specialist in
   some particular computing area.  The compounds "compiler jock"
   and "systems jock" seem to be the best-established examples.

   [Jargon File]

   (1995-01-19)