ruffian(n = noun.person) bully, hooligan, roughneck, rowdy, tough, yob, yobbo, yobo - a cruel and brutal fellow;
is a kind of aggressor, assailant, assaulter, attacker
has particulars: bullyboy, muscle, muscleman, skinhead, plug-ugly, tough guy
Derived form adjective ruffianly₁

1.  A pimp; a pander; also, a paramour. [1913 Webster]
"He [her husband] is no sooner abroad than she is instantly at home, reveling with her ruffians." [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?" [1913 Webster]

3.  A tough, lawless or bullying person. [1913 Webster]

   Brutal; cruel; savagely boisterous; murderous; as, ruffian rage. [1913 Webster]

   To play the ruffian; to rage; to raise tumult. Shak. [1913 Webster]

ruffian, n. a violent lawless person.

Derivative:
ruffianism n. ruffianly adv.

Etymology:
F ruf(f)ian f. It. ruffiano, perh. f. dial. rofia scurf

N  evil doer, evil worker, wrongdoer, mischief-maker, marplot, oppressor, tyrant, destroyer, Vandal, iconoclast, firebrand, incendiary, fire bug, pyromaniac, anarchist, communist, terrorist, savage, brute, ruffian, barbarian, semibarbarian, caitiff, desperado, Apache, hoodlum, hood, plug-ugly, Red Skin, tough, Mohawk, Mo-hock, Mo-hawk, bludgeon man, bully, rough, hooligan, larrikin, dangerous classes, ugly customer, thief, cockatrice, scorpion, hornet, snake, viper, adder, snake in the grass, serpent, cobra, asp, rattlesnake, anaconda, canker-worm, wire-worm, locust, Colorado beetle, alacran, alligator, caymon, crocodile, mosquito, mugger, octopus, torpedo, bane, cutthroat, cannibal, anthropophagus, anthropophagist, bloodsucker, vampire, ogre, ghoul, gorilla, vulture, gyrfalcon, gerfalcon, wild beast, tiger, hyena, butcher, hangman, blood-hound, hell- hound, sleuth-hound, catamount, cougar, jaguar, puma, hag, hellhag, beldam, Jezebel, monster, fiend, devil incarnate, demon in human shape, Frankenstein's monster, harpy, siren, Furies, Eumenides, Hun, Attila, scourge of the human race, faenum habet in cornu.

N  bad man, wrongdoer, worker of iniquity, evildoer, sinner, the wicked, bad example, villain, rascal, scoundrel, miscreant, budmash, caitiff, wretch, reptile, viper, serpent, cockatrice, basilisk, urchin, tiger, monster, devil, devil incarnate, demon in human shape, Nana Sahib, hellhound, hellcat, rakehell, bad woman, jade, Jezebel, scamp, scapegrace, rip, runagate, ne'er-do-well, reprobate, scalawag, scallawag, rou_e, rake, Sadist, skeesicks, skeezix, limb, one who has sold himself to the devil, fallen angel, ame damnee, vaurien, mauvais sujet, loose fish, sad dog, rounder, lost sheep, black sheep, castaway, recreant, defaulter, prodigal, rough, rowdy, hooligan, tough, ugly customer, mean mother, ruffian, bully, meanie, Jonathan Wild, hangman, incendiary, arsonist, fire bug, thief, murderer, terrorist, culprit, delinquent, crook, hoodlum, hood, criminal, thug, malefactor, offender, perpetrator, perp, disorderly person, misdemeanant, outlaw, scofflaw, vandal, felon, (convicted criminal), criminal, convict, prisoner, inmate, jail bird, ticket of leave man, multiple offender, blackguard, polisson, loafer, sneak, rapscallion, rascallion, cullion, mean wretch, varlet, kern, ame-de-boue, drole, cur, dog, hound, whelp, mongrel, lown, loon, runnion, outcast, vagabond, rogue, ronian, scum of the earth, riffraff, Arcades ambo, Int, sirrah!, Acherontis pabulum, gibier de potence.