The Collaborative International Dictionary of English v.0.48:

Samurai \Sa"mu*rai`\, n. pl. & sing. [Jap.]
   In the former feudal system of Japan, the class or a member
   of the class, of military retainers of the daimios,
   constituting the gentry or lesser nobility. They possessed
   power of life and death over the commoners, and wore two
   swords as their distinguishing mark. Their special rights and
   privileges were abolished with the fall of feudalism in 1871.
   They were referred to as "a cross between a knight and a
   gentleman".
   [Webster 1913 Suppl. +PJC]

The Collaborative International Dictionary of English v.0.48:

Shizoku \Shi*zo"ku\, n. sing. & pl. [Jap. shi-zoku, fr. Chin.
   ch' (chi) branch, posterity + tsu kindered, class.]
   The Japanese warrior gentry or middle class, formerly called
   samurai; also, any member of this class.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

samurai
    n 1: a Japanese warrior who was a member of the feudal military
         aristocracy
    2: feudal Japanese military aristocracy

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

samurai
 n.

    A hacker who hires out for legal cracking jobs, snooping for factions in
    corporate political fights, lawyers pursuing privacy-rights and First
    Amendment cases, and other parties with legitimate reasons to need an
    electronic locksmith. In 1991, mainstream media reported the existence of a
    loose-knit culture of samurai that meets electronically on BBS systems,
    mostly bright teenagers with personal micros; they have modeled themselves
    explicitly on the historical samurai of Japan and on the ?net cowboys? of
    William Gibson's cyberpunk novels. Those interviewed claim to adhere to a
    rigid ethic of loyalty to their employers and to disdain the vandalism and
    theft practiced by criminal crackers as beneath them and contrary to the
    hacker ethic; some quote Miyamoto Musashi's Book of Five Rings, a classic
    of historical samurai doctrine, in support of these principles. See also 
    sneaker, Stupids, social engineering, cracker, hacker ethic, and 
    dark-side hacker.


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

samurai

   A hacker who hires out for legal cracking jobs, snooping for
   factions in corporate political fights, lawyers pursuing
   privacy-rights and First Amendment cases, and other parties
   with legitimate reasons to need an electronic locksmith.  In
   1991, mainstream media reported the existence of a loose-knit
   culture of samurai that meets electronically on BBS systems,
   mostly bright teenagers with personal micros; they have
   modelled themselves explicitly on the historical samurai of
   Japan and on the "net cowboys" of William Gibson's cyberpunk
   novels.  Those interviewed claim to adhere to a rigid ethic of
   loyalty to their employers and to disdain the vandalism and
   theft practiced by criminal crackers as beneath them and
   contrary to the hacker ethic; some quote Miyamoto Musashi's
   "Book of Five Rings", a classic of historical samurai
   doctrine, in support of these principles.

   See also Stupids, social engineering, cracker, hacker
   ethic, and dark-side hacker.

   [Jargon File]