The Collaborative International Dictionary of English v.0.48:

Cowboy \Cow"boy`\ (-boi`), n.
   1. A cattle herder; a drover; specifically, one of an
      adventurous class of herders and drovers on the plains of
      the Western and Southwestern United States.
      [1913 Webster]

   2. One of the marauders who, in the Revolutionary War
      infested the neutral ground between the American and
      British lines, and committed depredations on the
      Americans.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

cowpoke \cowpoke\ n.
   a hired hand who tends cattle and performs other duties on
   horseback; -- an informal name for cowboy.

   Syn: cowboy, cowpuncher, puncher, cowman, cattleman, cowhand,
        cowherd.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

cowboy
    n 1: a hired hand who tends cattle and performs other duties on
         horseback [syn: cowboy, cowpuncher, puncher,
         cowman, cattleman, cowpoke, cowhand, cowherd]
    2: a performer who gives exhibitions of riding and roping and
       bulldogging [syn: cowboy, rodeo rider]
    3: someone who is reckless or irresponsible (especially in
       driving vehicles)

The Free On-line Dictionary of Computing (19 January 2023):

cowboy

   [Sun, from William Gibson's cyberpunk SF]  Synonym
   for hacker.  It is reported that at Sun this word is often
   said with reverence.

   [Jargon File]


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

cowboy
 n.

    [Sun, from William Gibson's cyberpunk SF] Synonym for hacker. It is
    reported that at Sun this word is often said with reverence.