The Collaborative International Dictionary of English v.0.48:

Ruffian \Ruf"fian\ (r[u^]f"yan or r[u^]f"f[i^]*an; 277), n. [F.
   rufien, OF. ruffien, ruffian, pimp, libertine, rake; cf. Pr.
   & Sp. rufian, It. ruffiano; all perhaps of German or Dutch
   origin; cf. G. raufen to pluck, scuffle, fight, OD. roffen to
   pander. Cf. Ruffle to grow turbulent.]
   1. A pimp; a pander; also, a paramour. [Obs.]
      [1913 Webster]

            He [her husband] is no sooner abroad than she is
            instantly at home, reveling with her ruffians. --Bp.
                                                  Reynolds.
      [1913 Webster]

   2. A boisterous, cruel, brutal fellow; a desperate fellow
      ready for murderous or cruel deeds; a cutthroat.
      [1913 Webster]

            Wilt thou on thy deathbed play the ruffian? --Shak.
      [1913 Webster]

   2. Hence: A tough, lawless or bullying person.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ruffian \Ruf"fian\, a.
   Brutal; cruel; savagely boisterous; murderous; as, ruffian
   rage.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ruffian \Ruf"fian\, v. i.
   To play the ruffian; to rage; to raise tumult. [R.] --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ruffian
    n 1: a cruel and brutal fellow [syn: bully, tough,
         hooligan, ruffian, roughneck, rowdy, yob, yobo,
         yobbo]

Moby Thesaurus II by Grady Ward, 1.0:

120 Moby Thesaurus words for "ruffian":
   Babbitt, Philistine, arriviste, bad boy, battler, belligerent,
   belted knight, bickerer, blade, booger, boor, bounder, bourgeois,
   bravo, brawler, bucko, buffoon, bugger, bully, bullyboy, cad,
   churl, clown, combatant, competitor, contender, contestant,
   cutthroat, cutup, desperado, devil, disputant, duelist, elf,
   enfant terrible, enforcer, epicier, fencer, feuder, fighter,
   fighting cock, foilsman, funmaker, gamecock, gladiator, goon,
   gorilla, groundling, gunman, guttersnipe, hatchet man, hell-raiser,
   hellcat, hood, hoodlum, hooligan, ill-bred fellow, imp, joker,
   jokester, jouster, killer, knave, knight, little devil,
   little monkey, little rascal, looby, lout, low fellow, mad dog,
   militant, minx, mischief, mischief-maker, mucker, nouveau riche,
   parvenu, peasant, pixie, plug-ugly, practical joker, prankster,
   puck, punk, quarreler, rapscallion, rascal, ribald, rioter, rival,
   rogue, rough, roughneck, rowdy, sabreur, scamp, scapegrace,
   scrapper, scuffler, squabbler, strong arm, strong-arm man,
   strong-armer, struggler, swashbuckler, sword, swordplayer,
   swordsman, thug, tilter, tough, tussler, upstart, vulgarian,
   vulgarist, wag, wrangler, yahoo, yokel