The Collaborative International Dictionary of English v.0.48:

linemen \linemen\ n. pl. lineman.
   the football players who line up on the line of scrimmage. WN
   hypen is odd for this def.
   [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Lineman \Line"man\ (l[imac]n"m[a^]n), n.; pl. Linemen
   (l[imac]n"m[e^]n).
   1. One who carries the line in surveying, etc.; the surveyor
      who marks positions with a range pole.
      [1913 Webster]

   2. A man employed to examine the rails of a railroad to see
      if they are in good condition; also, a man employed to
      install or repair telegraph, telephone, television cable,
      or power lines. Also called linesman.
      [1913 Webster]

   3. (Football) A player whose position is in the first
      (forward) line, as opposed to a back; one who plays on
      the line of scrimmage. specifically: a center, guard, or
      tackle.
      [PJC]

   4. A ladies' man who is especially adept at inventing
      effective introductory phrases (pick-up lines) to gain a
      woman's attention. [Colloq.]
      [1913 Webster]

   5. the position of a player on a football team who is
      stationed on the line of scrimmage. [WordNet sense 4]
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

lineman
    n 1: one of the players on the line of scrimmage
    2: the surveyor who marks positions with a range pole
    3: a person who installs or repairs electrical or telephone
       lines [syn: electrician, lineman, linesman]
    4: (American football) the position of a player on a football
       team who is stationed on the line of scrimmage

Moby Thesaurus II by Grady Ward, 1.0:

71 Moby Thesaurus words for "lineman":
   amateur athlete, archer, athlete, baggage man, bakehead,
   ballplayer, baseballer, baseman, batter, battery, blocking back,
   bowman, brakeman, brakie, butcher, catcher, center, coach,
   competitor, conductor, cricketer, defensive lineman, dispatcher,
   electrician, electrotechnician, end, fireman, footballer,
   footplate man, games-player, gamester, groundman, guard, infielder,
   jock, jumper, offensive lineman, outfield, outfielder, player,
   poloist, porter, professional athlete, pugilist, quarterback,
   racer, radio technician, railroad man, railroader, redcap, rigger,
   skater, smoke agent, sport, sportsman, stationmaster, stoker,
   switchman, tackle, tailback, telephone mechanic,
   telephonic engineer, toxophilite, trainboy, trainman, trainmaster,
   wingback, wireman, wrestler, yardman, yardmaster